android从系统图库中取图片的实例代码

package com.easymorse.gallery;import java.io.File;import android.app.Activity;import android.content.Intent;import android.graphics.drawable.Drawable;import android.net.Uri;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class GalleryActivity extends Activity { private static int SELECT_PICTURE; private File tempFile; Button button; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  this.tempFile=new File("/sdcard/a.jpg");  button = new Button(this);  button.setText("获取图片");  button.setOnClickListener(new OnClickListener() {   @Override   public void onClick(View v) {    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);    intent.setType("image/*");    intent.putExtra("crop", "true");    // intent.putExtra("aspectX", 1);    // intent.putExtra("aspectY", 2);    intent.putExtra("output", Uri.fromFile(tempFile));    intent.putExtra("outputFormat", "JPEG");    startActivityForResult(Intent.createChooser(intent, "选择图片"),      SELECT_PICTURE);   }  });  setContentView(button); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {  if (resultCode == RESULT_OK) {   if (requestCode == SELECT_PICTURE) {    button.setBackgroundDrawable(Drawable.createFromPath(tempFile      .getAbsolutePath()));   }  } }}