android自定义控件的一个思路-入门

转自：http://blog.sina.com.cn/s/blog_691051e10101a3by.html

 

很多时候没有我们需要使用的控件，或者控件并不美观。比如这个滑动开关，这是android之后的版本才提供的控件，新版本并不提供，这个时候就需要我们自定义控件了。

 

一个2个主要类，OnChangedListener，SlipButton

 

SlipButton代码如下

package com.appipv6.android.slipbutton;

 

import com.appipv.onoff.R;

import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.Canvas;

import android.graphics.Matrix;

import android.graphics.Paint;

import android.graphics.Rect;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

import android.view.View.OnTouchListener;

 

public class SlipButton extends View implements OnTouchListener

{

//当前按钮状态

private boolean nowChoose=false;  

//用户是否在滑动

private boolean onSlip=false;

//按下时的X，当时的X

private float downX,nowX;

//打开和关闭状态下的，游标的Rect

private Rect btn_On,btn_Off;

 

private boolean isChgLsnOn =false;  

private OnChangedListener ChgLsn;  

     

private Bitmap bg_on,bg_off,slip_btn;  

public SlipButton(Context context)

{

super(context);

// TODO Auto-generated constructor stub

init();

}

 

public SlipButton(Context context, AttributeSet attrs)

{

super(context, attrs);

// TODO Auto-generated constructor stub

init();

}

 

public SlipButton(Context context, AttributeSet attrs, int defStyle)

{

super(context, attrs, defStyle);

// TODO Auto-generated constructor stub

init();

}

 

private void init()

{

// TODO Auto-generated method stub

bg_on=BitmapFactory.decodeResource(getResources(), R.drawable.on);

bg_off=BitmapFactory.decodeResource(getResources(), R.drawable.off);

slip_btn=BitmapFactory.decodeResource(getResources(), R.drawable.my_btn);

int tmp=bg_off.getWidth()/2;

btn_On=new Rect(tmp, 0, slip_btn.getWidth()+tmp, slip_btn.getHeight());

btn_Off=new Rect(bg_off.getWidth()-tmp-slip_btn.getWidth(), 0, bg_off.getWidth()-tmp, slip_btn.getHeight());

setOnTouchListener(this);

}

@Override

protected void onDraw(Canvas canvas)

{

// TODO Auto-generated method stub

super.onDraw(canvas);

Matrix matrix=new Matrix();

Paint paint=new Paint();

float x;

if(onSlip)

{

if(nowX>=bg_on.getWidth())

{

x=bg_on.getWidth()-slip_btn.getWidth()/2;

}else{

x=nowX-slip_btn.getWidth()/2;

}

}else{

if(nowChoose)

{

x=btn_On.left;

}else{

x=btn_Off.left;

}

}

if(nowX<(bg_on.getWidth()/2))

{

canvas.drawBitmap(bg_off, matrix, paint);

}else{

canvas.drawBitmap(bg_on, matrix, paint);

}

if(x<0)

{

x=0;

}else if(x>bg_on.getWidth()-slip_btn.getWidth())

{

x=bg_on.getWidth()-slip_btn.getWidth();

}

canvas.drawBitmap(slip_btn, x, 0,paint);

}

 

public boolean onTouch(View v, MotionEvent event)

{

// TODO Auto-generated method stub

switch (event.getAction())

{

case MotionEvent.ACTION_MOVE:

nowX=event.getX();

break;

case MotionEvent.ACTION_DOWN:

if(event.getX()>bg_on.getWidth() || event.getY()>bg_on.getHeight())

{

return false;

}

onSlip=true;

downX=event.getX();

nowX=downX;

break;

case MotionEvent.ACTION_UP:

onSlip=false;

boolean lastChoose=nowChoose;

if(event.getX()>=(bg_on.getWidth()/2))

{

nowChoose=true;

}else{

nowChoose=false;

}

if(isChgLsnOn&&(lastChoose!=nowChoose))

{

ChgLsn.OnChanged(nowChoose);

}

break;

default:

break;

}

invalidate();

return true;

}

public void setOnChangeListener(OnChangedListener l)

{

isChgLsnOn=true;

ChgLsn=l;

}

 

public boolean isNowChoose()

{

return nowChoose;

}

 

public void setNowChoose(boolean nowChoose)

{

this.nowChoose = nowChoose;

nowX=btn_On.left;

invalidate();

}

 

}

 

 

OnChangedListener代码如下

public interface OnChangedListener

{

abstract void OnChanged(boolean CheckState);

}

 

 

主Activity代码如下

 

package com.appipv.onoff;

 

import com.appipv6.android.slipbutton.OnChangedListener;

import com.appipv6.android.slipbutton.SlipButton;

 

import android.app.Activity;

import android.os.Bundle;

import android.widget.Toast;

 

public class OnOffActivity extends Activity

{

private SlipButton slipButton1;

@Override

public void onCreate(Bundle savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

SlipButton slipButton = (SlipButton) findViewById(R.id.slipButton1);

slipButton.setNowChoose(true);

slipButton1 = (SlipButton) findViewById(R.id.slipButton2);

 

slipButton.setOnChangeListener(new OnChangedListener()

{

 

public void OnChanged(boolean CheckState)

{

// TODO Auto-generated method stub

String s;

if(slipButton1.isNowChoose())

{

s="Button2打开了...";

}else{

s="Button2关闭了...";

}

if (CheckState)

Toast.makeText(OnOffActivity.this, "Button1打开了..."+s,

Toast.LENGTH_SHORT).show();

else

Toast.makeText(OnOffActivity.this, "Button1关闭了..."+s,

Toast.LENGTH_SHORT).show();

}

});

}

}

布局文件代码如下

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical" 

    android:background="@drawable/back"

    >

 

    <com.appipv6.android.slipbutton.SlipButton

        android:id="@+id/slipButton1"

        android:layout_width="wrap_content"

        android:layout_height="49dp" />

 

 <com.appipv6.android.slipbutton.SlipButton

     android:id="@+id/slipButton2"

     android:layout_width="wrap_content"

     android:layout_height="fill_parent" />

 

</LinearLayout>