参考注释郭霖老师的Android相机程序
注释详细
1~main
package luyou.woyi.com.cameratest;
import android.annotation.TargetApi;
import android.content.ContentUris;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
public static final int TAKE_PHOTO = 1;
public static final int CROP_PHOTO = 2;
public static final int CHOOSE_PHOTO = 3;
private Button takephoto;
private Button choosephoto;
private ImageView picture;
private Uri imageUri;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
takephoto = (Button) findViewById(R.id.take_photo);
picture = (ImageView) findViewById(R.id.picture);
choosephoto = (Button) findViewById(R.id.choose_photo);
/*
* 实现监听器
* */
takephoto.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
/*
* 创建File对象，实现拍照图片的存储
* */
File outputImage = new File(Environment.getExternalStorageDirectory(),
"output_image.jpg");
/*
* 初始化图片
* */
try {
if (outputImage.exists()) {
outputImage.delete();
}
outputImage.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
/*
* 将File对象转成Uri对象
* */
imageUri = Uri.fromFile(outputImage);
/*
* 构建隐式Intent，指定图片输出地址
* */
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
/*
* 启动相机，并向下一个活动传递参数
* */
startActivityForResult(intent, TAKE_PHOTO);
}
});
choosephoto.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent("android.intent.action.GET_CONTENT");
intent.setType("image/*");
/*
* 打开相册
* */
startActivityForResult(intent, CHOOSE_PHOTO);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
/*
* 拍照成功返回结果，跳转到裁剪
* */
case TAKE_PHOTO:
if (resultCode == RESULT_OK) {
Intent intent = new Intent("com.android.camera.action.CROP");
intent.setDataAndType(imageUri, "image/*");
intent.putExtra("scale", true);
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
/*
* 启动剪裁程序
* */
startActivityForResult(intent, CROP_PHOTO);
}
break;
/*
* 裁剪结束，将.jpg解析成Bitmap显示出来
* */
case CROP_PHOTO:
if (resultCode == RESULT_OK) {
try {
Bitmap bitmap = BitmapFactory.decodeStream(
getContentResolver().openInputStream(imageUri));
picture.setImageBitmap(bitmap); //显示剪裁后的图片
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
break;
/*
* 判断版本，选择处理图片方式
* */
case CHOOSE_PHOTO:
if (resultCode == RESULT_OK) {
if (Build.VERSION.SDK_INT >= 19) {
/*
* 4.4及以上版本
* */
handleImageOnKitKat(data);
} else {
/*
* 4.4以下版本
* */
handleImageBeforeKitKat(data);
}
}
break;
default:
break;
}
}
/*
* 4.4以上版本需要封装Uri
* */
@TargetApi(19)
private void handleImageOnKitKat(Intent data) {
String imagePath = null;
/*
* 获取路径
* */
Uri uri = data.getData();
/*
*Document类型Uri对document id处理
* */
if (DocumentsContract.isDocumentUri(this, uri)) {
String docId = DocumentsContract.getDocumentId(uri);
/*
* 与Uri中Authority部分比较,media格式需进一步解析
* */
if ("com.android.providers.media.documents".equals(
uri.getAuthority())) {
String id = docId.split(":")[1];
String selection = MediaStore.Images.Media._ID + "=" + id;
/*
* 传入getImagePath获得真实路径
* */
imagePath = getImagePath(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);
} else if ("com.android.providers.downloads.documents".equals(
uri.getAuthority())) {
/*
* downloads格式获得路径
* */
Uri contentUri = ContentUris.withAppendedId(
Uri.parse("content://downloads/public_downloads"),
Long.valueOf(docId));
imagePath = getImagePath(contentUri, null);
}
} else if ("content".equalsIgnoreCase(uri.getScheme())) {
/*
* 普通处理
* */
imagePath = getImagePath(uri, null);
}
/*
* 图片显示
* */
displayImage(imagePath);
}
/*
* 4.4以下版本返回图片真实Uri，直接处理
* */
private void handleImageBeforeKitKat(Intent data) {
Uri uri = data.getData();
String imagePath = getImagePath(uri, null);
displayImage(imagePath);
}
/*
* 获取图片路径
* */
private String getImagePath(Uri uri, String selection) {
String path = null;
Cursor cursor = getContentResolver().query(uri, null, selection, null, null);
if (cursor != null) {
/*
* 定位第一行返回指定列名称
* */
if (cursor.moveToFirst()) {
path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
}
/*
* 释放资源
* */
cursor.close();
}
return path;
}
/*
* 打印图片
* */
private void displayImage(String imagePath) {
if (imagePath != null) {
/*
* 将照片解析为Bitmap形式展现
* */
Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
picture.setImageBitmap(bitmap);
} else {
Toast.makeText(this, "failed to get image", Toast.LENGTH_SHORT).show();
}
}
}
2~activity_layout.xml
没找到老师的源码地址，手打手打，若有不当还请指教