android 工程，点击图片，在屏幕显示

1：首先创建一个android 工程名字自定义（此处为MyTest)
2:替换MainActivity.java 代码如下

package com.example.mytest;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends Activity implements OnClickListener{

Button mButton;
ImageView mImageView;
TextView mTextView;
Bitmap bm;
private static final int REQUEST_CODE_SELECT_PIC = 120;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

//注册三个组件
mButton = (Button) findViewById(R.id.button1);
mImageView = (ImageView) findViewById(R.id.imageView1);
mTextView = (TextView) findViewById(R.id.textView1);

mButton.setOnClickListener(this);

}

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
if(arg0.getId() == R.id.button1)
{
selectPicture();
}

}

private void selectPicture() {
Intent intent = new Intent();
intent.setAction(Intent.ACTION_PICK);
intent.setType("image/*");
// 这个函数会自动调用下面的函数
startActivityForResult(intent, REQUEST_CODE_SELECT_PIC);
}

protected void onActivityResult(int requestCode, int resultCode, Intent data) {

if (requestCode == REQUEST_CODE_SELECT_PIC) {

// 获取选择的图片
Uri selectedImage = data.getData();
int width = 0;
int height = 0;

String[] filePathColumn = { MediaStore.Images.Media.DATA };
Cursor cursor = getContentResolver().query(selectedImage, null,
null, null, null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
// 获取到图片的路径
String selectedImagePath = cursor.getString(columnIndex);

Log.i("zhang selectedImagePath", selectedImagePath);
// 调取底层处理
//DealImage(selectedImagePath);
// 解码该路径的图片，得到bitmap 图片

bm = BitmapFactory.decodeFile(selectedImagePath);

width = bm.getWidth();
height = bm.getHeight();

if (selectedImage != null)
{
//将图片显示到ImageView中
mImageView.setImageBitmap(bm);

}

}
super.onActivityResult(requestCode, resultCode, data);
}

}
3： 替换res 下的layout 文件夹下面的 activity_main.xml ，代码如下
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="TextView" />

<ImageView
android:id="@+id/imageView1"
android:layout_width="240dp"
android:layout_height="240dp"
android:layout_marginLeft="0dp"
android:layout_marginTop="0dp"
android:layout_x="116dp"
android:layout_y="26dp"
android:src="@drawable/ic_launcher" />

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="84dp"
android:layout_x="25dp"
android:layout_y="63dp"
android:text="Button" />

</LinearLayout>
4：在AndroidManifest.xml 文件中加入权限

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
<uses-permission android:name="android.permission.SYSTEM_OVERLAY_WINDOW" />
<uses-permission android:name="android.permission.MOUNT_FORMAT_FILESYSTEMS" />
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_LOGS" />
<uses-permission android:name="com.qti.permission.PROFILER" />

5:完成，烧写程序。