Android从相册中选择图片显示出来

下面的两篇博客我是选择其中的一部分使用的。大家可以自己试试。第一篇：http://blog.csdn.net/jackyguo1992/article/details/26729107

一、选择图片

定义Intent跳转到特定图库的Uri下挑选，然后将挑选结果返回给Activity用到startActivityForResult[java] viewplain copy Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);  startActivityForResult(intent, RESULT);  然后在onActivityForResult保存

二、图片缩放

这里讲的很详细http://blog.csdn.net/lincyang/article/details/6651582照它所说有3种方法：第一种是BitmapFactory和BitmapFactory.Options，同比例缩放，但是效率高第二种是使用Bitmap加Matrix来缩放，能够不同比例，但是效率低第三种是用2.2新加的类ThumbnailUtils来做，这方法不懂，好复杂。。我用第一种，将图片放在Imageview中[java] viewplain copy private void showPhoto(ImageView photo){      String picturePath = target.getInfo(Target.TargetPhotoPath);// 图片的uri      if(picturePath.equals(""))          return;      // 缩放图片, width, height 按相同比例缩放图片         BitmapFactory.Options options = new BitmapFactory.Options();         // options 设为true时，构造出的bitmap没有图片，只有一些长宽等配置信息，但比较快，设为false时，才有图片         options.inJustDecodeBounds = true;         Bitmap bitmap = BitmapFactory.decodeFile(picturePath, options);         int scale = (int)( options.outWidth / (float)300);         if(scale <= 0)          scale = 1;         options.inSampleSize = scale;         options.inJustDecodeBounds = false;         bitmap = BitmapFactory.decodeFile(picturePath, options);                  photo.setImageBitmap(bitmap);         photo.setMaxHeight(350);  }  

三、代码

[java] viewplain copy public class RemindActivity extends Activity {        private ImageView photo;      private static final int RESULT = 1;      Target target;            @Override      protected void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.activity_remind);                            photo = (ImageView)findViewById(R.id.photo);          target = new Target(this);                    showPhoto(photo);                    photo.setOnClickListener(new OnClickListener(){                @Override              public void onClick(View arg0) {                  // TODO Auto-generated method stub                  Dialog dialog = new AlertDialog.Builder(RemindActivity.this)                  .setTitle("从图库里选择照片").setMessage("确定要更换照片？").setPositiveButton("确定",                           new DialogInterface.OnClickListener() {                                                            @Override                              public void onClick(DialogInterface dialog, int which) {                                  // TODO Auto-generated method stub                                  Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);                                  startActivityForResult(intent, RESULT);                              }                          }).setNegativeButton("取消", new DialogInterface.OnClickListener() {                                                            @Override                              public void onClick(DialogInterface dialog, int which) {                                  // TODO Auto-generated method stub                                  dialog.cancel();                              }                          }).create();                  dialog.show();              }                        });                }            @Override      protected void onActivityResult(int requestCode, int resultCode, Intent data) {          // TODO Auto-generated method stub          super.onActivityResult(requestCode, resultCode, data);          if(requestCode == RESULT && resultCode == RESULT_OK && data != null){                            Uri selectedImage = data.getData();              String[] filePathColumn = { MediaStore.Images.Media.DATA };                 Cursor cursor = getContentResolver().query(selectedImage,                      filePathColumn, null, null, null);              cursor.moveToFirst();                 int columnIndex = cursor.getColumnIndex(filePathColumn[0]);              String picturePath = cursor.getString(columnIndex);              cursor.close();                 target.setInfo(Target.TargetPhotoPath, picturePath);                            showPhoto(photo);          }      }            private void showPhoto(ImageView photo){          String picturePath = target.getInfo(Target.TargetPhotoPath);          if(picturePath.equals(""))              return;          // 缩放图片, width, height 按相同比例缩放图片          BitmapFactory.Options options = new BitmapFactory.Options();          // options 设为true时，构造出的bitmap没有图片，只有一些长宽等配置信息，但比较快，设为false时，才有图片          options.inJustDecodeBounds = true;          Bitmap bitmap = BitmapFactory.decodeFile(picturePath, options);          int scale = (int)( options.outWidth / (float)300);          if(scale <= 0)              scale = 1;          options.inSampleSize = scale;          options.inJustDecodeBounds = false;          bitmap = BitmapFactory.decodeFile(picturePath, options);                    photo.setImageBitmap(bitmap);          photo.setMaxHeight(350);      }  

第二篇地址：http://www.oschina.net/question/234345_40138

public class Lesson_01_Pic extends Activity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);Button button = (Button)findViewById(R.id.b01);button.setText("选择图片");button.setOnClickListener(new Button.OnClickListener(){@Overridepublic void onClick(View v) {Intent intent = new Intent();/* 开启Pictures画面Type设定为image */intent.setType("image/*");/* 使用Intent.ACTION_GET_CONTENT这个Action */intent.setAction(Intent.ACTION_GET_CONTENT);/* 取得相片后返回本画面 */startActivityForResult(intent, 1);}});}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {if (resultCode == RESULT_OK) {Uri uri = data.getData();Log.e("uri", uri.toString());ContentResolver cr = this.getContentResolver();try {Bitmap bitmap = BitmapFactory.decodeStream(cr.openInputStream(uri));ImageView imageView = (ImageView) findViewById(R.id.iv01);/* 将Bitmap设定到ImageView */imageView.setImageBitmap(bitmap);} catch (FileNotFoundException e) {Log.e("Exception", e.getMessage(),e);}}super.onActivityResult(requestCode, resultCode, data);}}