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] view plain 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] view plain 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] view plain 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. */    @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(){@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);}}

一、选择图片

二、图片缩放

三、代码

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