ProgressDialog 使用

最新推荐文章于 2025-04-19 07:02:13 发布

原创最新推荐文章于 2025-04-19 07:02:13 发布 · 154 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#thread #J# #工作

anddev 专栏收录该内容

95 篇文章

订阅专栏

本文介绍了一个使用ProgressDialog的示例，在Android应用中展示一个进度对话框，同时在后台线程执行耗时任务。示例从100倒计数至0，并在完成时关闭ProgressDialog。

ProgressDialog

[功能]
ProgressDialog 也是一种Dialog
一般在出现ProgressDialog 后台都会再开辟Thread 来做一些耗时的工作我演示的是从100数到0 这段时间既不太长不用浪费时间等待同时也能明显地看出效果

[代码]
1. ProgressDialog 使用


public void startProgress(){
    	//to start Progress
    	pd = ProgressDialog.show(this, "loop from 100 to 0!", "is looping...", true,
    			false);
    	//pd.setIcon(R.drawable.icon);
    }

2. 开辟一个Thread来从100数到0 在数完后关闭ProgressDialog


public class TaskLoop implements Runnable {
		@Override
		public void run() {
			// TODO Auto-generated method stub
			loop(5000);

			messageListener.sendEmptyMessage(TASK_LOOP_COMPLETE);
		}

    }

public void loop(long i){
    	long j = i;
    	while(j>0){
    		Log.d("tag",j+"");

    		j = j-1;
		}

    }

3. 运行该Thread


Thread loop = new Thread(new TaskLoop());
loop.start();

4.定义一个Handler 用于接受关闭ProgressDialog 的通知


private Handler messageListener = new Handler(){
    	public void handleMessage(Message msg) {
			switch(msg.arg1){
			case TASK_LOOP_COMPLETE:
				pd.dismiss();
				break;

			}
		}
    };

[所有代码]


public class MyProgressUsage extends Activity {
	public final static int TASK_LOOP_COMPLETE = 0;

	ProgressDialog pd;

	TextView tv;
	/** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        findViewById(R.id.start).setOnClickListener(new OnClickListener(){
			public void onClick(View v) {
				// TODO Auto-generated method stub
				startLoop();
			}
        });
    }

    public void startLoop(){

    	startProgress();

    	Thread loop = new Thread(new TaskLoop());
    	loop.start();
    }


    public class TaskLoop implements Runnable {
		@Override
		public void run() {
			// TODO Auto-generated method stub
			loop(5000);

			messageListener.sendEmptyMessage(TASK_LOOP_COMPLETE);
		}

    }

    public void startProgress(){
    	//to start Progress
    	pd = ProgressDialog.show(this, "loop from 100 to 0!", "is looping...", true,
    			false);
    	//pd.setIcon(R.drawable.icon);
    }

    //to do some time-cost task
    public void loop(long i){
    	long j = i;
    	while(j>0){
    		Log.d("tag",j+"");

    		j = j-1;
		}

    }

    private Handler messageListener = new Handler(){
    	public void handleMessage(Message msg) {
			switch(msg.arg1){
			case TASK_LOOP_COMPLETE:
				pd.dismiss();
				break;

			}
		}
    };

}