android studio网络图片浏览器

.xml

,java
package com.example.abc.imageview;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.Message;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class MainActivity extends ActionBarActivity {
protected static final int CHANGE_UI = 1;
protected static final int ERROR = 2;
private EditText et_path;
private ImageView ivPic;
private Handler handler = new Handler(){
public void handleMessage(android.os.Message msg){
if (msg.what == CHANGE_UI){
Bitmap bitmap = (Bitmap) msg.obj;
ivPic.setImageBitmap(bitmap);
}else if (msg.what == ERROR){
Toast.makeText(MainActivity.this,“显示图片错误”, Toast.LENGTH_SHORT).show();
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et_path = (EditText) findViewById(R.id.et_path);
ivPic = (ImageView) findViewById(R.id.iv_pic);
}
public void click(View view){
final String path = et_path.getText().toString().trim();
if (TextUtils.isEmpty(path)){
Toast.makeText(this,“图片路径不能为空”, Toast.LENGTH_SHORT).show();
}else {
new Thread() {
private HttpURLConnection conn;
private Bitmap bitmap;

            public void run() {
                try {
                    URL url = new URL(path);
                    conn = (HttpURLConnection) url.openConnection();
                    conn.setRequestMethod("GET");
                    conn.setConnectTimeout(5000);
                    int code = conn.getResponseCode();
                    if (code == 200) {
                        InputStream is = conn.getInputStream();
                        bitmap = BitmapFactory.decodeStream(is);
                        Message msg = new Message();
                        msg.what = CHANGE_UI;
                        msg.obj = bitmap;
                        handler.sendMessage(msg);
                    } else {
                        Message msg = new Message();
                        msg.what = ERROR;
                        handler.sendMessage(msg);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                    Message msg = new Message();
                    msg.what = ERROR;
                    handler.sendMessage(msg);
                }
                conn.disconnect();
            }
        }.start();
    }
}

}