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874天前1.MainActivity.java |
package com.example.acer.myapplication; |
import android.app.ProgressDialog; |
import android.os.Handler; |
import android.os.Message; |
import android.support.v7.app.AppCompatActivity; |
import android.os.Bundle; |
import android.view.View; |
import android.widget.Button; |
import android.widget.TextView; |
public class MainActivity extends AppCompatActivity { |
private TextView statusTextView; |
private Button beginBtn; |
private ProgressDialog progressDialog; |
@Override |
public void onCreate(Bundle savedInstanceState) { |
super.onCreate(savedInstanceState); |
setContentView(R.layout.activity_main); |
statusTextView = (TextView)findViewById(R.id.status); |
beginBtn = (Button)findViewById(R.id.beginBtn); |
} |
//更新UI |
private Handler handler = new Handler(){ |
@Override |
public void handleMessage(Message msg) { |
//关闭ProgressDialog |
progressDialog.dismiss(); |
//更新UI |
statusTextView.setText("完成!"); |
}}; |
|
public void onClick(View v) { |
//显示ProgressDialog |
progressDialog = ProgressDialog.show(MainActivity.this, "Loading...", "Please wait...", true, false); |
//新建线程 |
new Thread(){ |
public void run() { |
//需要花时间计算的方法 |
Calculation.calculate(4); |
//向handler发消息 |
handler.sendEmptyMessage(0); |
}}.start(); |
} |
} |
2.activity_main.xml |
<?xml version="1.0" encoding="utf-8"?> |
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" |
android:orientation="vertical" |
android:layout_width="fill_parent" |
android:layout_height="fill_parent" |
> |
<TextView android:id="@+id/status" |
android:layout_width="fill_parent" |
android:layout_height="wrap_content" |
android:text="hello" |
/> |
<Button android:id="@+id/beginBtn" |
android:layout_width="fill_parent" |
android:layout_height="wrap_content" |
android:text="begin" |
android:onClick="onClick" /> |
</LinearLayout> |
3.Calculation.java |
package com.example.acer.myapplication; |
public class Calculation { |
public static void calculate(int sleepSeconds){ |
try { |
Thread.sleep(sleepSeconds * 1000); |
} catch (Exception e) { |
// TODO: handle exception |
} |
} |
} |
