以下为代码块：

package com.example.demo;

import java.io.File;

import android.annotation.TargetApi;

import android.app.Activity;

import android.content.ContentUris;

import android.content.Intent;

import android.database.Cursor;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.net.Uri;

import android.os.Build;

import android.os.Bundle;

import android.os.Environment;

import android.provider.DocumentsContract;

import android.provider.MediaStore;

import android.provider.MediaStore.Audio.Media;

import android.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.ImageView;

import android.widget.Toast;

public class MainActivity extends Activity {

public static final int TAKE_PHOTO = 1;

public static final int CROP_PHOTO = 2;

public static final int CHOOSE_PH = 3;

Button b, chooseFromAlbum;

ImageView pictrue;

Uri imageUri;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

b = (Button) findViewById(R.id.button1);

chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);

pictrue = (ImageView) findViewById(R.id.imageView1);

chooseFromAlbum.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

Intent intent = new Intent("android.intent.action.GET_CONTENT");

intent.setType("image/*");

startActivityForResult(intent,CHOOSE_PH);//打开相册。

}

});

b.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

File outputImage = new File(Environment

.getExternalStorageDirectory(), "output_image.jpg");// Environment.getExternalStorageDirectory()获取SD卡的根目录.

try {

if (outputImage.exists()) {

outputImage.delete();

}

outputImage.createNewFile();

} catch (Exception e) {

// TODO: handle exception

}

imageUri = Uri.fromFile(outputImage);

Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");

intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);// 个人理解拍完放在imageUri下。

startActivityForResult(intent, TAKE_PHOTO);// 启动相机程序。

}

});

}

@Override

protected void onActivityResult(int requestCode, int resultCode, Intent data) {// requestCode:拍完照传回1，裁剪完传回2。

switch (requestCode) {

case TAKE_PHOTO:

if (resultCode == RESULT_OK) {

try {

Intent intent = new Intent("com.android.camera.action.CROP");

intent.setDataAndType(imageUri, "image/*");

intent.putExtra("scale", true);

intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);// 剪完放在放在imageUri下。

startActivityForResult(intent, CROP_PHOTO);// 启动裁剪程序。

} catch (Exception e) {

Log.i("test", "e=" + e);

}

}

break;

case CROP_PHOTO:

if (resultCode == RESULT_OK) {

try {

Bitmap bitMap = BitmapFactory

.decodeStream(getContentResolver().openInputStream(

imageUri));// 解码。

Log.i("test", "bitMap=" + bitMap);

pictrue.setImageBitmap(bitMap);// 将裁减的图片显示出来。

} catch (Exception e) {

Log.i("test", "e1=" + e);

}

}

break;

case CHOOSE_PH:

if(resultCode == RESULT_OK ){

//判断当前系统版本。

if(Build.VERSION.SDK_INT>=19){

//

4.4以上的系统版本使用这个方法处理。

handleImageOnKitKat(data);

}else{

//

4.4以下的系统版本使用这个方法处理。

handleImageBeforeKitKat(data);

}

}

break;

default:

break;

}

}

@TargetApi(19)

private void handleImageOnKitKat(Intent data){

String imagePath = null;

Uri uri = data.getData();

Log.i("test","4.4以上uri="+uri);

if(DocumentsContract.isDocumentUri(this, uri)){

String docId = DocumentsContract.getDocumentId(uri);

if("com.android.providers.media.documents".equals(uri.getAuthority())){

String id = docId.split(":")[1];

String selection = MediaStore.Images.Media._ID+"="+id;

imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,selection);

}else if("com.android.providers.downloads.documents".equals(uri.getAuthority())){

Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(docId));

imagePath = getImagePath(contentUri,null);

}

}else if("content".equalsIgnoreCase(uri.getScheme())){

imagePath = getImagePath(uri,null);

}

//imagePath此时的路径为真实的手机图片的路径。

displayImage(imagePath);

}

private void handleImageBeforeKitKat(Intent data){

Uri uri = data.getData();

String imagePath = getImagePath(uri,null);

//imagePath此时的路径为真实的手机图片的路径。

displayImage(imagePath);

}

private String getImagePath(Uri uri,String selection){

String path = null;

//

getContentResolver：获得内容解析；query：查询。

Cursor cursor = getContentResolver().query(uri, null, selection, null, null);

if(cursor!=null){

if(cursor.moveToFirst()){

//

getColumnIndex：获得列索引。

path = cursor.getString(cursor.getColumnIndex(Media.DATA));

}

cursor.close();

}

return path;

}

private void displayImage(String imagePath){

if(imagePath!=null){

Bitmap bitmap = BitmapFactory.decodeFile(imagePath);

pictrue.setImageBitmap(bitmap);

}else{

Toast.makeText(this, "错误！", Toast.LENGTH_LONG).show();

}

}

}

以下为AndroidManifest.xml文件内容：

package="com.example.demo"

android:versionCode="1"

android:versionName="1.0" >

android:minSdkVersion="14"

android:targetSdkVersion="19" />

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

android:name=".MainActivity"

android:label="@string/app_name" >

以下为简单的布局文件：

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context="com.example.choosepictest.MainActivity" >

android:id="@+id/button1"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_alignParentLeft="true"

android:layout_alignParentTop="true"

android:text="打开相机" />

android:id="@+id/imageView1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignLeft="@+id/button1"

android:layout_below="@+id/button1"

android:layout_marginTop="131dp" />

android:id="@+id/choose_from_album"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_alignLeft="@+id/button1"

android:layout_below="@+id/button1"

android:layout_marginTop="26dp"

android:text="打开相册" />