Android学习之自定义控件

常用的自定义控件的方式大致有三种：

1.继承自现有控件，加以改进，如继承TextView；

2.将几种控件进行组合，构成新的组件；

3.继承View类，重绘一个组件。

自定义控件的方法：

首先定义一个自定义控件类(MyView.java)：

</pre><pre name="code" class="html">package com.jtext.chessdisplay;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;

public class MyView extends View{

Context context1;
// TODO Auto-generated constructor stub
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
context1=context;
// TODO Auto-generated constructor stub
}

@Override
protected void onDraw(Canvas canvas){
super.onDraw(canvas);
Paint paint=new Paint();
paint.setColor(Color.RED);
paint.setShadowLayer(2, 3, 4, Color.GRAY);
Rect r=new Rect(40,40,200,100);
canvas.drawRect(r,paint);
paint.setColor(Color.BLUE);
canvas.drawText("自定义控件测试", 40, 40, paint);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
switch (event.getAction()){
case MotionEvent.ACTION_DOWN:
Toast.makeText(context1, "自定义组件测试",0).show();
break;
case MotionEvent.ACTION_MOVE:
Toast.makeText(context1, "HUAHUA",0).show();
break;
}
return super.onTouchEvent(event);

}

}

接着，就可以像普通控件一样，在布局里声明使用（myview.xml）：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<com.jtext.chessdisplay.MyView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/myView"
/>
</LinearLayout>

最后，在MainActivity里显示：

package com.jtext.chessdisplay;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {
MyView2 mv;
MyView2 mv1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.myview);}
}

二、组合控件

以继承布局类来自定义控件为例.

布局myview2

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/iv"
android:layout_gravity="center_vertical"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/tv"
android:layout_gravity="center_vertical"
android:gravity="center_horizontal"/>
</LinearLayout>

控件定义MyView2.java

package com.jtext.chessdisplay;

import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

public class MyView2 extends LinearLayout{
private ImageView iv;
private TextView tv;
int i=0;
Context context1;
public MyView2(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
inflater.inflate(R.layout.myview2, this);
iv=(ImageView) findViewById(R.id.iv);
tv=(TextView)findViewById(R.id.tv);
context1=context;
iv.setOnTouchListener(new myTouchListener());
}
public void setImageResource(int resid){
iv.setImageResource(resid);
}
public void setTextView(String str,int color){
tv.setText(str);
tv.setTextColor(color);
}
class myTouchListener implements  OnTouchListener {

@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
switch (v.getId()){
case R.id.iv:
i++;
Toast.makeText(context1, "数量更改成功", 0).show();
tv.setText(i+"");;
break;
}
return false;
}

}
}

MainActivity里进行显示：

package com.jtext.chessdisplay;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {
MyView2 mv;
MyView2 mv1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.myview3);
mv=(MyView2)findViewById(R.id.mv);
mv1=(MyView2)findViewById(R.id.mv1);
mv.setImageResource(R.drawable.cart);
mv.setTextView("测试", Color.RED);
mv1.setImageResource(R.drawable.cart);
mv1.setTextView("测试", Color.BLUE);
}
}