Android长按imageview把图片保存到本地

rxjava版本：

    compile 'io.reactivex:rxjava:1.1.5'
    compile 'io.reactivex:rxandroid:1.2.0'

示例代码：

public class MainActivity extends AppCompatActivity {

    private ImageView imageView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageView = (ImageView) findViewById(R.id.imageview);
        findViewById(R.id.btn_save).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                saveImageView(getViewBitmap(imageView));
            }
        });
    }

    private class SaveObservable implements Observable.OnSubscribe {

        private Bitmap drawingCache = null;

        public SaveObservable(Bitmap drawingCache) {
            this.drawingCache = drawingCache;
        }

        @Override
        public void call(Subscriber subscriber) {
            if (drawingCache == null) {
                subscriber.onError(new NullPointerException("imageview的bitmap获取为null,请确认imageview显示图片了"));
            } else {
                try {
                    File imageFile = new File(Environment.getExternalStorageDirectory(), "saveImageview.jpg");
                    FileOutputStream outStream;
                    outStream = new FileOutputStream(imageFile);
                    drawingCache.compress(Bitmap.CompressFormat.JPEG, 100, outStream);
                    subscriber.onNext(Environment.getExternalStorageDirectory().getPath());
                    subscriber.onCompleted();
                    outStream.flush();
                    outStream.close();
                } catch (IOException e) {
                    subscriber.onError(e);
                }
            }
        }
    }

    private class SaveSubscriber extends Subscriber {

        @Override
        public void onCompleted() {
            Toast.makeText(getApplicationContext(), "保存成功", Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onError(Throwable e) {
            Log.i(getClass().getSimpleName(), e.toString());
            Toast.makeText(getApplicationContext(), "保存失败——> " + e.toString(), Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onNext(String s) {
            Toast.makeText(getApplicationContext(), "保存路径为：-->  " + s, Toast.LENGTH_SHORT).show();
        }
    }


    private void saveImageView(Bitmap drawingCache) {
        Observable.create(new SaveObservable(drawingCache))
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new SaveSubscriber());
    }

    /**
     * 某些机型直接获取会为null,在这里处理一下防止国内某些机型返回null
     */
    private Bitmap getViewBitmap(View view) {
        if (view == null) {
            return null;
        }
        Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        view.draw(canvas);
        return bitmap;
    }
}

//不建议使用

package com.app.mly.utils;

import android.app.Activity;
import android.graphics.Bitmap;
import android.os.AsyncTask;
import android.os.Environment;
import android.widget.ImageView;
import android.widget.Toast;

import com.fengche.android.mly.R;

import java.io.File;
import java.io.FileOutputStream;

/**
 * Created by y on 2016/1/14.
 */
public class SaveImageUtils extends AsyncTask {
    Activity mActivity;
    ImageView mImageView;

    public SaveImageUtils(Activity activity, ImageView imageView) {
        this.mImageView = imageView;
        this.mActivity = activity;
    }

    @Override
    protected String doInBackground(Bitmap... params) {
        String result = mActivity.getResources().getString(R.string.save_picture_failed);
        try {
            String sdcard = Environment.getExternalStorageDirectory().toString();
            File file = new File(sdcard + "/123");
            if (!file.exists()) {
                file.mkdirs();
            }
            File imageFile = new File(file.getAbsolutePath(), "命名" + ".jpg");
            FileOutputStream outStream = null;
            outStream = new FileOutputStream(imageFile);
            Bitmap image = params[0];
            image.compress(Bitmap.CompressFormat.JPEG, 100, outStream);
            outStream.flush();
            outStream.close();
            result = mActivity.getResources().getString(R.string.save_picture_success, file.getAbsolutePath());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }

    @Override
    protected void onPostExecute(String result) {
        Toast.makeText(mActivity, result, Toast.LENGTH_SHORT).show();
        mImageView.setDrawingCacheEnabled(false);
    }
}

stirng文件下需要的几个toast

    保存图片
    保存失败
    图片成功保存至%s目录

代码中引用

 mScanCode.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                AlertDialog.Builder builder = new AlertDialog.Builder(ShareActivity.this);
                builder.setItems(new String[]{getResources().getString(R.string.save_picture)}, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        mScanCode.setDrawingCacheEnabled(true);
                        Bitmap imageBitmap = mScanCode.getDrawingCache();
                        if (imageBitmap != null) {
                            new SaveImageUtils(ShareActivity.this, mScanCode).execute(imageBitmap);
                        }
                    }
                });
                builder.show();
                return true;
            }
        });