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

 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

 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

 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. */
    @Override
    public 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(){
			@Override
			public 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);
			}
        	
        });
    }
    
	@Override
	protected 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);
	}
}