android程式設計實例入門 -Sample改寫分享 (2014/09/12)

android程式設計實例入門 -Sample改寫分享 (2014/09/12)

 

此範例為程式碼(03\Sample7)的改寫，利用一個LinearLayout、一個TextView和一個Button元件實作GUI界面，並且利用SampleTouchListener讓按鈕擁有Touch事件反應能力另外在Activity上實作Touch+KeyDown事件讓Activity也擁有Touch+KeyDown事件反應能力，程式碼如下所示：

 

 

package com.jashsample;

import android.os.Bundle;
import android.app.Activity;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;

public class MainActivity extends Activity {
	public TextView tv;
	public Button bt;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
	      LinearLayout ll = new LinearLayout(this); 
	      ll.setOrientation(LinearLayout.VERTICAL);
	      setContentView(ll);
	      
	      tv = new TextView(this);
	      tv.setText("歡迎光臨。");
	      bt = new Button(this);
	      bt.setText("購買");

	      ll.addView(tv);
	      ll.addView(bt);
	 
	      bt.setOnTouchListener(new SampleTouchListener());//Touch事件
	}
	public boolean onKeyDown(int keycode, KeyEvent e)//直接在Activity上實作KeyDown事件
	{
		String str;
		switch(keycode)
		{
			case KeyEvent.KEYCODE_DPAD_UP:
				str = "上";
				break;
			case KeyEvent.KEYCODE_DPAD_DOWN:
				str = "下";
				break;        	  
			case KeyEvent.KEYCODE_DPAD_LEFT:
				str = "左";
				break;      
			case KeyEvent.KEYCODE_DPAD_RIGHT:
				str = "右";
				break;      
			case KeyEvent.KEYCODE_DPAD_CENTER:
				str = "中央";
				break;
			default:
				str = "其他按鍵";
		}
		tv.setText("��" + str + "。");
	      
		return true;
	}
	public boolean onTouchEvent(MotionEvent e)//直接在Activity上實作Touch事件
	{
		if(e.getAction() == MotionEvent.ACTION_DOWN)//設定在畫面任何地方Touch都改變tv文字
		{
			tv.setText("您好再見");
		}
		else if(e.getAction() == MotionEvent.ACTION_UP)
		{
			tv.setText("再見您好");
		}
		return true;
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}
	class SampleTouchListener implements OnTouchListener
	{
		public boolean onTouch(View v, MotionEvent e)
		{
			if(e.getAction() == MotionEvent.ACTION_DOWN)
	    	 {
	            tv.setText("您好");
	         }
	         else if(e.getAction() == MotionEvent.ACTION_UP)
	         {
	            tv.setText("再見");
	         }
	         return true;
	      }
	}
	class SampleClickListener implements OnClickListener//按鈕事件反��類別
	{
		public void onClick(View v)
		{
	         tv.setText("謝謝惠顧。");
		}
	} 
}