控制toast出现位置以及progressbar的出现消失-优快云博客

本文链接：https://blog.youkuaiyun.com/iteye_15461/article/details/81861852

本文提供两个Android应用示例：一是展示如何使用Toast显示消息；二是演示如何使用ProgressDialog及Handler进行后台任务处理，包括创建ProgressDialog、启动长时间运行的任务以及通过Handler更新UI。

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import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

/**
 * Class which shows how to show toast
 * @author FaYnaSoft Labs
 */
public class Main extends Activity {

    private Button clickBtn;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        clickBtn = (Button) findViewById(R.id.click);
        clickBtn.setText("Show message");
        clickBtn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                Toast msg = Toast.makeText(Main.this, "Message", Toast.LENGTH_LONG);
                msg.setGravity(Gravity.CENTER, msg.getXOffset() / 2, msg.getYOffset() / 2);
                msg.show();
            }
        });
    }
}

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

/**
 * Class which shows how to work with handler class
 * @author FaYnaSoft Labs
 */
public class Main extends Activity {

    private Button clickBtn;
    private ProgressDialog progressDialog;
    private Handler handler = new Handler() {

        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            progressDialog.dismiss();
        }
    };

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        clickBtn = (Button) findViewById(R.id.click);
        clickBtn.setText("Click me");
        clickBtn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                processThread();
            }
        });
    }

    private void processThread() {
        progressDialog = ProgressDialog.show(Main.this, "", "Doing...");
        new Thread() {
            public void run() {
                longTimeMethod();
                handler.sendEmptyMessage(0);
            }
        }.start();
    }

    private void longTimeMethod() {
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            Log.e("tag", e.getMessage());
        }
    }
}