实现查看网络图片功能

public class MainActivity extends AppCompatActivity {protected static final int CHANGE_UI = 1;
protected static final int ERROR = 2;
private EditText et_path;
private ImageView iv;
private Handler handler = new Handler(){
public void handleMessage(android.os.Message msg) {
if(msg.what == CHANGE_UI){
Bitmap bitmap = (Bitmap) msg.obj;
iv.setImageBitmap(bitmap);
}else if(msg.what == ERROR){
Toast.makeText(MainActivity.this, "显示图片错误", Toast.LENGTH_SHORT).show();
}
};
};
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et_path = (EditText) findViewById(R.id.et_path);
iv = (ImageView) findViewById(R.id.iv);
}
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() {
public void run() {
try {
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url
.openConnection();
conn.setRequestMethod("GET");
conn.setConnectTimeout(5000);
int code = conn.getResponseCode();
if (code == 200) {
InputStream is = conn.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(is);
//iv.setImageBitmap(bitmap);
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);
}
}
}.start();
}
}}

import java.util.Date;public class ThreadClassDemo {public static void main(String[] args) {
// TODO Auto-generated method stub
ClockThread clockThread = new ClockThread();
//      clockThread.start();
//  Thread thread = new Thread(clockThread);
//thread.start();
new Thread(new Runnable(){
@Override
public void run(){
while (true){
System.out.println(new Date());
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
System.out.println("main");}}
class ClockThread implements Runnable{ //extend Thread
@Override
public void run(){
//super.run();
while(true){
System.out.println(new Date());
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}}
}