android控件ImageView加载sdcard卡，网络及res中的图片

最新推荐文章于 2025-05-10 19:41:23 发布

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最新推荐文章于 2025-05-10 19:41:23 发布

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分类专栏： Android 文章标签： imageView加载图片

本文链接：https://blog.youkuaiyun.com/sky_0035/article/details/51534712

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本文介绍了Android中如何使用ImageView加载res/drawable资源、SD卡中的图片以及网络上的图像资源。强调了加载网络图片时需要在后台线程执行，并推荐使用android-async-http库进行异步加载。

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提前声明

加载网络资源需要网络访问权限：

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

加载sd卡中的资源则需要权限：

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

不然，不然，代码正确，但一直会抛异常哟因为没权限呀没权限

效果图：

一：

先说访问res/drawable/下的图片的访问方法中，因为这种最简单，getResources()是Context的方法。

myPic.setImageDrawable(getResources().getDrawable(R.drawable.ic_launcher));

二：

访问本地SD卡中的图片

				String path=Environment.getExternalStorageDirectory().toString()+"/aa.jpg";
				Bitmap bitmap = getLoacalBitmap(path); //从本地取图片

三：

访问网络上的图片资源

这种情况下，要注意一下，android不允许在在跟界面操作所在的线程中加入会导致程序反应迟钝的操作，譬如上网加载网上的数据，这些操作，要实现就一定得放到其他线程中去执行。这里，为了简便起见，咱们就直接用网上的async-http开源框架好了，内部实现原理就是开线程专门加载资源，加载完再反馈界面主线程。

操作起来还算简单，记得下载android-async-http-1.4.6.jar包，我用的1.4.6 后面的版本会出点问题。

				String url="http://img.club.pchome.net/upload/club/other/2015/6/24/pics_kdsxxoo_1435102809.jpg";
				AsyncHttpClient client=new AsyncHttpClient();
				
	            client.get(url, new AsyncHttpResponseHandler(){  
	                @Override  
	                public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {  
	                    if(statusCode==200){  
	                        BitmapFactory factory=new BitmapFactory();  
	                        Bitmap bitmap=factory.decodeByteArray(responseBody, 0, responseBody.length);  
	                        myPic.setImageBitmap(bitmap);  
	                    }  
	                }  
	                  
	                @Override  
	                public void onFailure(int statusCode, Header[] headers,  
	                        byte[] responseBody, Throwable error) {  
	                    error.printStackTrace();  
	                }  
	            });

源码：

activity_main.xml

<RelativeLayout 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"
    tools:context="com.liang.test1.MainActivity" >

    <ImageView 
        android:id="@+id/mypic" 
        android:layout_width="400dp"
        android:layout_height="400dp"
        android:layout_centerInParent="true"
        android:scaleY="3"
        android:scaleX="1.5"
        android:rotationY="35"
        android:src="@drawable/aaa"/>

</RelativeLayout>

MainActivity.java

package com.liang.test1;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import org.apache.http.Header;

import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.view.animation.RotateAnimation;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener{

private static final String TAG = "MAIN_ACTIVITY";
	//	private Button leftBottomBut;
//	private Button rightBottomBut;
//	private Button leftTopBut;
	//	private Button rightTopBut;
	private ImageView myPic;
	private AlphaAnimation myAnimation_Alpha;
	private RotateAnimation myAnimation_Rotate;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		this.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
		setContentView(R.layout.activity_main);
		myPic=(ImageView)findViewById(R.id.mypic);
		myPic.setOnClickListener(new View.OnClickListener() {
			
			@Override
			public void onClick(View arg0) {
				// TODO Auto-generated method stub
				String url="http://img.club.pchome.net/upload/club/other/2015/6/24/pics_kdsxxoo_1435102809.jpg";
				AsyncHttpClient client=new AsyncHttpClient();
				
	            client.get(url, new AsyncHttpResponseHandler(){  
	                @Override  
	                public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {  
	                    if(statusCode==200){  
	                        BitmapFactory factory=new BitmapFactory();  
	                        Bitmap bitmap=factory.decodeByteArray(responseBody, 0, responseBody.length);  
	                        myPic.setImageBitmap(bitmap);  
	                    }  
	                }  
	                  
	                @Override  
	                public void onFailure(int statusCode, Header[] headers,  
	                        byte[] responseBody, Throwable error) {  
	                    error.printStackTrace();  
	                }  
	            });
				
				Toast.makeText(MainActivity.this, "pic was clicked", Toast.LENGTH_SHORT).show();
//				 Bitmap bitmap =getHttpBitmap("http://blog.3gstdy.com/wp-content/themes/twentyten/images/headers/path.jpg");
				String path=Environment.getExternalStorageDirectory().toString()+"/aa.jpg";
				Bitmap bitmap = getLoacalBitmap(path); //从本地取图片
//				myPic.setImageDrawable(getResources().getDrawable(R.drawable.ic_launcher));

				 myPic.setImageBitmap(bitmap);
				 //				AlphaAnimation(float fromAlpha, float toAlpha) 
				//说明:0.0表示完全透明,1.0表示完全不透明
				myAnimation_Rotate=new RotateAnimation(0.0f, +350.0f,Animation.RELATIVE_TO_SELF,0.5f,Animation.RELATIVE_TO_SELF, 0.5f);
				
				myAnimation_Alpha=new AlphaAnimation(0.1f, 1.0f);
				myAnimation_Rotate.setDuration(5000);
				myPic.setAnimation(myAnimation_Rotate);
				myAnimation_Rotate.start();
			}
		});
//		leftBottomBut=(Button)findViewById(R.id.left_bottom_but);
//		leftBottomBut.setOnClickListener(this);
//		rightBottomBut=(Button)findViewById(R.id.right_bottom_but);
//		rightBottomBut.setOnClickListener(this);
//		leftTopBut=(Button)findViewById(R.id.left_top_but);
//		leftTopBut.setOnClickListener(new View.OnClickListener() {
//
//			@Override
//			public void onClick(View arg0) {
//				// TODO Auto-generated method stub
//				Toast.makeText(MainActivity.this, "left_top_but clicked", Toast.LENGTH_SHORT).show();
//			}
//		});
		//		rightTopBut=(Button)findViewById(R.id.right_top_but);
		//		rightTopBut.setOnClickListener(this);
	}

	
	/**
	* 加载本地图片
	* http://bbs.3gstdy.com
	* @param url
	* @return
	*/
	public static Bitmap getLoacalBitmap(String url) {
	     try {
	          FileInputStream fis = new FileInputStream(url);
	          return BitmapFactory.decodeStream(fis);
	     } catch (FileNotFoundException e) {
	          e.printStackTrace();
	          return null;
	     }
	}
	
	public static Bitmap getHttpBitmap(String url) {
	     URL myFileUrl = null;
	     Bitmap bitmap = null;
	     try {
	          Log.d(TAG, url);
	          myFileUrl = new URL(url);
	     } catch (MalformedURLException e) {
	          e.printStackTrace();
	     }
	     try {
	          HttpURLConnection conn = (HttpURLConnection) myFileUrl.openConnection();
	          conn.setConnectTimeout(0);
	          conn.setDoInput(true);
	          conn.connect();
	          InputStream is = conn.getInputStream();
	          bitmap = BitmapFactory.decodeStream(is);
	          is.close();
	     } catch (IOException e) {
	          e.printStackTrace();
	     }
	     return bitmap;
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		// Handle action bar item clicks here. The action bar will
		// automatically handle clicks on the Home/Up button, so long
		// as you specify a parent activity in AndroidManifest.xml.
		int id = item.getItemId();
		if (id == R.id.action_settings) {
			return true;
		}
		return super.onOptionsItemSelected(item);
	}

	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
//		switch(v.getId())
//		{
//		case R.id.left_bottom_but:
//			Toast.makeText(this, "left_bottom_but clicked", Toast.LENGTH_SHORT).show();
//			break;
//		case R.id.right_bottom_but:
//			Toast.makeText(this, "right_bottom_but clicked", Toast.LENGTH_SHORT).show();
//			break;
//		default:
//			break;
//		}
	}

	public void butclicked(View v)
	{
//		switch(v.getId())
//		{
//		case R.id.right_top_but:
//			Toast.makeText(this, "right_top_but clicked", Toast.LENGTH_SHORT).show();
//			break;
//		default:
//			break;
//		}
	}
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.liang.test1"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="15"
        android:targetSdkVersion="15" />

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>