017_03获取图库图片

　　当需要在之前Activity中得到新打开Activity的数据，需要系统提供的startActivityForResult(Intent intent,int requestCode)方法。为了取得传回的数据，需要在之前的Activity中重写onActivityResult(int requestCode, int resultCode,Intent data)方法。

package com.example.day17_03getExif;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    
    public void getpicturefromgallery(View v){
        
        Intent intent = new Intent();
        intent.setAction("android.intent.action.PICK");
        intent.setType("image/*");
        startActivityForResult(intent, 100);     
    }
    
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {    
        if (requestCode==100 &&resultCode==RESULT_OK ) {
            //resultcode ok才可以从里面去获取你要的数据
            System.out.println("MainActivity.onActivityResult()"+resultCode);
            ImageView iv_photo = (ImageView) findViewById(R.id.iv_photo);
            
            Uri uri =data.getData();
            System.out.println(uri);
            iv_photo.setImageURI(uri);
            
            System.out.println("MainActivity.onActivityResult()"+uri.toString());        
            String[] filePathColumn = { MediaStore.Images.Media.DATA };
            Cursor cursor=    getContentResolver().query(uri, filePathColumn, null, null, null);
            cursor.moveToNext();    
            String filepath = cursor.getString(0);
            System.out.println("MainActivity.onActivityResult()"+filepath);  
        }    
    }    
}

<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: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.day17_03getExif.MainActivity"
    android:orientation="vertical" >
    
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="获取图库图片" 
        android:onClick="getpicturefromgallery"/>
    
    <ImageView
        android:id="@+id/iv_photo"  
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
        
</LinearLayout>

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>