Android 疯狂造轮子 常用工具类 直接拿来用！

转载请注明出处： http://blog.csdn.net/smartbetter/article/details/52709446

本篇用于分享Android开发辅助工具类，用于快速开发，以便减少做重复的工作，提高开发效率。项目代码长期更新于Github：https://github.com/smartbetter/Android-UtilsLibrary

1.AppUtils（App相关辅助类）

public class AppUtils {

    private AppUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 获取应用程序名称 */
    public static String getAppName(Context context) {
        try {
            PackageManager packageManager = context.getPackageManager();
            PackageInfo packageInfo = packageManager.getPackageInfo(context.getPackageName(), 0);
            int labelRes = packageInfo.applicationInfo.labelRes;
            return context.getResources().getString(labelRes);
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }

    /** * 获取应用程序版本名称信息 */
    public static String getVersionName(Context context) {
        try {
            PackageManager packageManager = context.getPackageManager();
            PackageInfo packageInfo = packageManager.getPackageInfo(context.getPackageName(), 0);
            return packageInfo.versionName; // 当前应用的版本名称
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }

}

2.CameraUtils（摄像头相关辅助类）

public class CameraUtils {

    private CameraUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 判断摄像头是否可用 */
    public static boolean isCameraCanUse() {
        boolean canUse = true;
        Camera mCamera = null;
        try {
            mCamera = Camera.open();
            // setParameters 是针对魅族MX5 做的。MX5 通过Camera.open() 拿到的Camera
            // 对象不为null
            Camera.Parameters mParameters = mCamera.getParameters();
            mCamera.setParameters(mParameters);
        } catch (Exception e) {
            canUse = false;
        }
        if (mCamera != null) {
            mCamera.release();
        }
        return canUse;
    }

}

3.DensityUtils(android dp和px之间转换)

public class DensityUtils {

    private DensityUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 根据手机的分辨率从 dip 的单位 转成为 px(像素) */
    public static int qip2px(Context context, float dpValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }

    /** * 根据手机的分辨率从 px(像素) 的单位 转成为 dp */
    public static int px2dip(Context context, float pxValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (pxValue / scale + 0.5f);
    }

}

4.FileUtils（文件的基本操作）

主要封装了一些文件操作的基本方法，包括创建、删除、获取文件大小等。

public class FileUtils {

    private FileUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 检查是否存在SD卡 */
    public static boolean hasSdcard() {
        String state = Environment.getExternalStorageState();
        if (state.equals(Environment.MEDIA_MOUNTED)) {
            return true;
        } else {
            return false;
        }
    }

    /** * 创建目录 * * @param context * @param dirName 文件夹名称 * @return */
    public static File createFileDir(Context context, String dirName) {
        String filePath;
        // 如SD卡已存在，则存储；反之存在data目录下
        if (hasSdcard()) {
            // SD卡路径
            filePath = Environment.getExternalStorageDirectory() + File.separator + dirName;
        } else {
            filePath = context.getCacheDir().getPath() + File.separator + dirName;
        }
        File destDir = new File(filePath);
        if (!destDir.exists()) {
            boolean isCreate = destDir.mkdirs();
            Log.i("FileUtils", filePath + " has created. " + isCreate);
        }
        return destDir;
    }

    /** * 删除文件（若为目录，则递归删除子目录和文件） * * @param file * @param delThisPath true代表删除参数指定file，false代表保留参数指定file */
    public static void delFile(File file, boolean delThisPath) {
        if (!file.exists()) {
            return;
        }
        if (file.isDirectory()) {
            File[] subFiles = file.listFiles();
            if (subFiles != null) {
                int num = subFiles.length;
                // 删除子目录和文件
                for (int i = 0; i < num; i++) {
                    delFile(subFiles[i], true);
                }
            }
        }
        if (delThisPath) {
            file.delete();
        }
    }

    /** * 获取文件大小，单位为byte（若为目录，则包括所有子目录和文件） * * @param file * @return */
    public static long getFileSize(File file) {
        long size = 0;
        if (file.exists()) {
            if (file.isDirectory()) {
                File[] subFiles = file.listFiles();
                if (subFiles != null) {
                    int num = subFiles.length;
                    for (int i = 0; i < num; i++) {
                        size += getFileSize(subFiles[i]);
                    }
                }
            } else {
                size += file.length();
            }
        }
        return size;
    }

    /** * 保存Bitmap到指定目录 * * @param dir 目录 * @param fileName 文件名 * @param bitmap * @throws IOException */
    public static void saveBitmap(File dir, String fileName, Bitmap bitmap) {
        if (bitmap == null) {
            return;
        }
        File file = new File(dir, fileName);
        try {
            file.createNewFile();
            FileOutputStream fos = new FileOutputStream(file);
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
            fos.flush();
            fos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /** * 判断某目录下文件是否存在 * * @param dir 目录 * @param fileName 文件名 * @return */
    public static boolean isFileExists(File dir, String fileName) {
        return new File(dir, fileName).exists();
    }

}

5.HttpUtils（Http相关辅助类）

public class HttpUtils {

    private HttpUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    private static final int TIMEOUT_IN_MILLIONS = 5000;

    public interface CallBack {
        void onRequestComplete(String result);
    }

    /** * 异步的Get请求 * * @param urlStr * @param callBack */
    public static void doGetAsyn(final String urlStr, final CallBack callBack) {
        new Thread() {
            public void run() {
                try {
                    String result = doGet(urlStr);
                    if (callBack != null) {
                        callBack.onRequestComplete(result);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

            ;
        }.start();
    }

    /** * 异步的Post请求 * * @param urlStr * @param params * @param callBack * @throws Exception */
    public static void doPostAsyn(final String urlStr, final String params,
                                  final CallBack callBack) throws Exception {
        new Thread() {
            public void run() {
                try {
                    String result = doPost(urlStr, params);
                    if (callBack != null) {
                        callBack.onRequestComplete(result);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

            ;
        }.start();
    }

    /** * Get请求，获得返回数据 * * @param urlStr * @return * @throws Exception */
    public static String doGet(String urlStr) {
        URL url = null;
        HttpURLConnection conn = null;
        InputStream is = null;
        ByteArrayOutputStream baos = null;
        try {
            url = new URL(urlStr);
            conn = (HttpURLConnection) url.openConnection();
            conn.setReadTimeout(TIMEOUT_IN_MILLIONS);
            conn.setConnectTimeout(TIMEOUT_IN_MILLIONS);
            conn.setRequestMethod("GET");
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            if (conn.getResponseCode() == 200) {
                is = conn.getInputStream();
                baos = new ByteArrayOutputStream();
                int len = -1;
                byte[] buf = new byte[128];

                while ((len = is.read(buf)) != -1) {
                    baos.write(buf, 0, len);
                }
                baos.flush();
                return baos.toString();
            } else {
                throw new RuntimeException(" responseCode is not 200 ... ");
            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (is != null)
                    is.close();
            } catch (IOException e) {
            }
            try {
                if (baos != null)
                    baos.close();
            } catch (IOException e) {
            }
            conn.disconnect();
        }
        return null;
    }

    /** * 向指定 URL 发送POST方法的请求 * * @param url 发送请求的 URL * @param param 请求参数，形式:name1=value1&name2=value2 * @return 所代表远程资源的响应结果 * @throws Exception */
    public static String doPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            HttpURLConnection conn = (HttpURLConnection) realUrl
                    .openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type",
                    "application/x-www-form-urlencoded");
            conn.setRequestProperty("charset", "utf-8");
            conn.setUseCaches(false);
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setReadTimeout(TIMEOUT_IN_MILLIONS);
            conn.setConnectTimeout(TIMEOUT_IN_MILLIONS);
            if (param != null && !param.trim().equals("")) {
                // 获取URLConnection对象对应的输出流
                out = new PrintWriter(conn.getOutputStream());
                // 发送请求参数
                out.print(param);
                // flush输出流的缓冲
                out.flush();
            }
            // 定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(
                    new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 使用finally块来关闭输出流、输入流
        finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        return result;
    }

}

6.KeyBoardUtils（软键盘相关辅助类）

public class KeyBoardUtils {

    private KeyBoardUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 切换软键盘的状态 * 如当前为收起变为弹出,若当前为弹出变为收起 */
    public static void toggleKeybord(EditText edittext) {
        InputMethodManager inputMethodManager = (InputMethodManager)
                edittext.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
        inputMethodManager.toggleSoftInput(0, InputMethodManager.HIDE_NOT_ALWAYS);
    }

    /** * 强制隐藏输入法键盘 */
    public static void hideKeybord(EditText edittext) {
        InputMethodManager inputMethodManager = (InputMethodManager)
                edittext.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
        if (inputMethodManager.isActive()) {
            inputMethodManager.hideSoftInputFromWindow(edittext.getWindowToken(), 0);
        }
    }

    /** * 强制显示输入法键盘 */
    public static void showKeybord(EditText edittext) {
        InputMethodManager inputMethodManager = (InputMethodManager)
                edittext.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
        inputMethodManager.showSoftInput(edittext, InputMethodManager.SHOW_FORCED);
    }

    /** * 输入法是否显示 */
    public static boolean isKeybord(EditText edittext) {
        boolean bool = false;
        InputMethodManager inputMethodManager = (InputMethodManager)
                edittext.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
        if (inputMethodManager.isActive()) {
            bool = true;
        }
        return bool;
    }

}

7.LogUtils

public class LogUtils {

    private LogUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    private static boolean isDebug = false;

    public static void i(String tag, String msg) {
        if (isDebug) {
            Log.i(tag, msg);
        }
    }

    public static void i(Object object, String msg) {
        if (isDebug) {
            Log.i(object.getClass().getSimpleName(), msg);
        }
    }

    public static void e(String tag, String msg) {
        if (isDebug) {
            Log.e(tag, msg);
        }
    }

    public static void e(Object object, String msg) {
        if (isDebug) {
            Log.e(object.getClass().getSimpleName(), msg);
        }
    }

}

8.NetUtils（网络相关）

public class NetUtils {

    private NetUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 判断网络是否连接 */
    public static boolean isConnected(Context context) {
        ConnectivityManager connectivity = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        if (null != connectivity) {
            NetworkInfo info = connectivity.getActiveNetworkInfo();
            if (null != info && info.isConnected()) {
                if (info.getState() == NetworkInfo.State.CONNECTED) {
                    return true;
                }
            }
        }
        return false;
    }

    /** * 是否有网络，需要加上访问网络状态的权限 */
    public static boolean hasNetwork(Context context) {
        ConnectivityManager con = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo workinfo = con.getActiveNetworkInfo();
        if (workinfo == null || !workinfo.isAvailable()) {
            return false;
        }
        return true;
    }

    /** * 判断是否是WiFi网络 */
    public static boolean isWifiNet(Context context) {
        ConnectivityManager con = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo workinfo = con.getActiveNetworkInfo();
        return workinfo != null
                && workinfo.getType() == ConnectivityManager.TYPE_WIFI;
    }

    /** * 打开网络设置界面 */
    public static void openSetting(Activity activity) {
        //整体
        activity.startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS));
        //WIFI:
        //activity.startActivity(new Intent(Settings.ACTION_WIFI_SETTINGS));
        //流量:
        //activity.startActivity(new Intent(android.provider.Settings.ACTION_DATA_ROAMING_SETTINGS));
    }

}

9.ScreenUtils（屏幕相关）

public class ScreenUtils {

    private ScreenUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 获得屏幕高度 */
    public static int getScreenWidth(Context context) {
        WindowManager wm = (WindowManager) context
                .getSystemService(Context.WINDOW_SERVICE);
        DisplayMetrics outMetrics = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(outMetrics);
        return outMetrics.widthPixels;
    }

    /** * 获得屏幕宽度 */
    public static int getScreenHeight(Context context) {
        WindowManager wm = (WindowManager) context
                .getSystemService(Context.WINDOW_SERVICE);
        DisplayMetrics outMetrics = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(outMetrics);
        return outMetrics.heightPixels;
    }

    /** * 获得状态栏的高度 */
    public static int getStatusHeight(Context context) {
        int statusHeight = -1;
        try {
            Class<?> clazz = Class.forName("com.android.internal.R$dimen");
            Object object = clazz.newInstance();
            int height = Integer.parseInt(clazz.getField("status_bar_height")
                    .get(object).toString());
            statusHeight = context.getResources().getDimensionPixelSize(height);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return statusHeight;
    }

    /** * 获取当前屏幕截图，包含状态栏 */
    public static Bitmap snapShotWithStatusBar(Activity activity) {
        View view = activity.getWindow().getDecorView();
        view.setDrawingCacheEnabled(true);
        view.buildDrawingCache();
        Bitmap bmp = view.getDrawingCache();
        int width = getScreenWidth(activity);
        int height = getScreenHeight(activity);
        Bitmap bp = null;
        bp = Bitmap.createBitmap(bmp, 0, 0, width, height);
        view.destroyDrawingCache();
        return bp;
    }

    /** * 获取当前屏幕截图，不包含状态栏 */
    public static Bitmap snapShotWithoutStatusBar(Activity activity) {
        View view = activity.getWindow().getDecorView();
        view.setDrawingCacheEnabled(true);
        view.buildDrawingCache();
        Bitmap bmp = view.getDrawingCache();
        Rect frame = new Rect();
        activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
        int statusBarHeight = frame.top;

        int width = getScreenWidth(activity);
        int height = getScreenHeight(activity);
        Bitmap bp = null;
        bp = Bitmap.createBitmap(bmp, 0, statusBarHeight, width, height
                - statusBarHeight);
        view.destroyDrawingCache();
        return bp;
    }

}

10.SDCardUtils（SD卡相关）

public class SDCardUtils {

    private SDCardUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 判断SDCard是否可用 */
    public static boolean isSDCardEnable() {
        return Environment.getExternalStorageState().equals(
                Environment.MEDIA_MOUNTED);
    }

    /** * 获取SD卡路径 */
    public static String getSDCardPath() {
        return Environment.getExternalStorageDirectory().getAbsolutePath()
                + File.separator;
    }

    /** * 获取SD卡的剩余容量(byte) */
    public static long getSDCardAllSize() {
        if (isSDCardEnable()) {
            StatFs stat = new StatFs(getSDCardPath());
            // 获取空闲的数据块的数量
            long availableBlocks = (long) stat.getAvailableBlocks() - 4;
            // 获取单个数据块的大小（byte）
            long freeBlocks = stat.getAvailableBlocks();
            return freeBlocks * availableBlocks;
        }
        return 0;
    }

    /** * 获取指定路径所在空间的剩余可用容量字节数(byte) * @param filePath * @return 容量字节 SDCard可用空间，内部存储可用空间 */
    public static long getFreeBytes(String filePath) {
        // 如果是sd卡的下的路径，则获取sd卡可用容量
        if (filePath.startsWith(getSDCardPath())) {
            filePath = getSDCardPath();
        } else {// 如果是内部存储的路径，则获取内存存储的可用容量
            filePath = Environment.getDataDirectory().getAbsolutePath();
        }
        StatFs stat = new StatFs(filePath);
        long availableBlocks = (long) stat.getAvailableBlocks() - 4;
        return stat.getBlockSize() * availableBlocks;
    }

    /** * 获取系统存储路径 */
    public static String getRootDirectoryPath() {
        return Environment.getRootDirectory().getAbsolutePath();
    }

}

11.SPUtils

public class SPUtils {

    private SPUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 保存文件名 */
    public static final String FILE_NAME = "config";

    /** * 保存数据的方法，根据类型调用不同的保存方法 */
    public static void put(Context context, String key, Object object) {

        SharedPreferences sp = context.getSharedPreferences(FILE_NAME,
                Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sp.edit();

        if (object instanceof String) {
            editor.putString(key, (String) object);
        } else if (object instanceof Integer) {
            editor.putInt(key, (Integer) object);
        } else if (object instanceof Boolean) {
            editor.putBoolean(key, (Boolean) object);
        } else if (object instanceof Float) {
            editor.putFloat(key, (Float) object);
        } else if (object instanceof Long) {
            editor.putLong(key, (Long) object);
        } else {
            editor.putString(key, object.toString());
        }
        SharedPreferencesCompat.apply(editor); //commit同步的，apply异步的
    }

    /** * 获取数据的方法，根据默认值得到数据的类型，然后调用对应方法获取值 */
    public static Object get(Context context, String key, Object defaultObject) {
        SharedPreferences sp = context.getSharedPreferences(FILE_NAME,
                Context.MODE_PRIVATE);

        if (defaultObject instanceof String) {
            return sp.getString(key, (String) defaultObject);
        } else if (defaultObject instanceof Integer) {
            return sp.getInt(key, (Integer) defaultObject);
        } else if (defaultObject instanceof Boolean) {
            return sp.getBoolean(key, (Boolean) defaultObject);
        } else if (defaultObject instanceof Float) {
            return sp.getFloat(key, (Float) defaultObject);
        } else if (defaultObject instanceof Long) {
            return sp.getLong(key, (Long) defaultObject);
        }
        return null;
    }

    /** * 移除某个key对应的值 */
    public static void remove(Context context, String key) {
        SharedPreferences sp = context.getSharedPreferences(FILE_NAME,
                Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sp.edit();
        editor.remove(key);
        SharedPreferencesCompat.apply(editor);
    }

    /** * 清除所有数据 */
    public static void clear(Context context) {
        SharedPreferences sp = context.getSharedPreferences(FILE_NAME,
                Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sp.edit();
        editor.clear();
        SharedPreferencesCompat.apply(editor);
    }

    /** * 查询某个key是否已经存在 */
    public static boolean contains(Context context, String key) {
        SharedPreferences sp = context.getSharedPreferences(FILE_NAME,
                Context.MODE_PRIVATE);
        return sp.contains(key);
    }

    /** * 返回所有的键值对 */
    public static Map<String, ?> getAll(Context context) {
        SharedPreferences sp = context.getSharedPreferences(FILE_NAME,
                Context.MODE_PRIVATE);
        return sp.getAll();
    }

    /** * 创建一个解决SharedPreferencesCompat.apply方法的一个兼容类（适配） */
    private static class SharedPreferencesCompat {
        private static final Method sApplyMethod = findApplyMethod();

        /** * 反射查找apply的方法 */
        @SuppressWarnings({"unchecked", "rawtypes"})
        private static Method findApplyMethod() {
            try {
                Class clz = SharedPreferences.Editor.class;
                return clz.getMethod("apply");
            } catch (NoSuchMethodException e) {
            }
            return null;
        }

        /** * 如果找到则使用apply执行，否则使用commit */
        public static void apply(SharedPreferences.Editor editor) {
            try {
                if (sApplyMethod != null) {
                    sApplyMethod.invoke(editor);
                    return;
                }
            } catch (IllegalArgumentException e) {
            } catch (IllegalAccessException e) {
            } catch (InvocationTargetException e) {
            }
            editor.commit();
        }
    }

}

12.ToastUtils

public class ToastUtils {

    private ToastUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 短时间显示Toast */
    public static void showShort(Context context, CharSequence message) {
        Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
    }

    /** * 长时间显示Toast */
    public static void showLong(Context context, CharSequence message) {
        Toast.makeText(context, message, Toast.LENGTH_LONG).show();
    }

}

13.ViewUtils

public class ViewUtils {

    private ViewUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 把自身从父View中移除 */
    public static void removeSelfFromParent(View view) {
        if (view != null) {
            ViewParent parent = view.getParent();
            if (parent != null && parent instanceof ViewGroup) {
                ViewGroup group = (ViewGroup) parent;
                group.removeView(view);
            }
        }
    }

    /** * 判断触点是否落在该View上 */
    public static boolean isTouchInView(MotionEvent ev, View v) {
        int[] vLoc = new int[2];
        v.getLocationOnScreen(vLoc);
        float motionX = ev.getRawX();
        float motionY = ev.getRawY();
        return motionX >= vLoc[0] && motionX <= (vLoc[0] + v.getWidth())
                && motionY >= vLoc[1] && motionY <= (vLoc[1] + v.getHeight());
    }

}

除了以上常用工具类，还提供了对一些常用开源框架的辅助工具类，如下：

14.GlideUtils（Glide框架相关）

/** * 用Glide框架加载图片的时候根据图片尺寸让ImageView自适应 * Created by gc on 2016/11/6. */
public class GlideUtils {

    private GlideUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 加载图片 * @param view * @param url * @param targetWidth */
    public static void loadImage(ImageView view, String url, final int targetWidth) {
        Glide.with(view.getContext())
                .load(url)
                .into(new ImageViewTarget<GlideDrawable>(view) {
                    @Override
                    protected void setResource(GlideDrawable resource) {
                        autoFit(view, targetWidth, resource.getIntrinsicWidth(), resource.getIntrinsicHeight());
                        view.setImageDrawable(resource);
                    }
                });
    }

    public static void autoFit(ImageView imageView, int targetWidth, int photoWidth, int photoHeight) {
        float ratio = (targetWidth + 0f) / photoWidth;
        ViewGroup.LayoutParams params = imageView.getLayoutParams();
        if (params == null) {
            params = new ViewGroup.LayoutParams(targetWidth, (int) (photoHeight * ratio));
        } else {
            params.width = targetWidth;
            params.height = (int) (photoHeight * ratio);
        }
        imageView.setLayoutParams(params);
    }

}

15.GsonUtils

public class GsonUtils {

    private GsonUtils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /** * 把一个map变成json字符串 * * @param map * @return */
    public static String parseMapToJson(Map<?, ?> map) {
        try {
            Gson gson = new Gson();
            return gson.toJson(map);
        } catch (Exception e) {
        }
        return null;
    }

    /** * 把一个json字符串变成对象 * * @param json * @param cls * @return */
    public static <T> T parseJsonToBean(String json, Class<T> cls) {
        Gson gson = new Gson();
        T t = null;
        try {
            t = gson.fromJson(json, cls);
        } catch (Exception e) {
        }
        return t;
    }

    /** * 把json字符串变成map * * @param json * @return */
    public static HashMap<String, Object> parseJsonToMap(String json) {
        Gson gson = new Gson();
        Type type = new TypeToken<HashMap<String, Object>>() {
        }.getType();
        HashMap<String, Object> map = null;
        try {
            map = gson.fromJson(json, type);
        } catch (Exception e) {
        }
        return map;
    }

    /** * 把json字符串变成集合 * params: new TypeToken<List<yourbean>>(){}.getType(), * * @param json * @param type new TypeToken<List<yourbean>>(){}.getType() * @return */
    public static List<?> parseJsonToList(String json, Type type) {
        Gson gson = new Gson();
        List<?> list = gson.fromJson(json, type);
        return list;
    }

    /** * 获取json串中某个字段的值，注意，只能获取同一层级的value * * @param json * @param key * @return */
    public static String getFieldValue(String json, String key) {
        if (TextUtils.isEmpty(json))
            return null;
        if (!json.contains(key))
            return "";
        JSONObject jsonObject = null;
        String value = null;
        try {
            jsonObject = new JSONObject(json);
            value = jsonObject.getString(key);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return value;
    }

}

如果有更好的建议或者更好的Utils，请发私信或者留言。