Android--动态添加控件

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package com.mrzhu.edittest;

import android.app.Activity;
import android.os.Bundle;
import android.view.ViewGroup;
import android.widget.RelativeLayout;

public class EditTestActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//自定义的带提示文本的EditText组件
EditTextTest ed = new EditTextTest(this);
//设置从左边140px处开始输入文本
ed.setPadding(140, 0, 0, 0);
//装载一个布局文件，向这个布局中动态添加一个EditText
RelativeLayout relativeLayout = (RelativeLayout) getLayoutInflater().inflate(R.layout.main, null);
//创建一个LayoutParams对象
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
//设置android:layout_below属性的值
layoutParams.addRule(RelativeLayout.BELOW, R.id.button2);
//动态添加EditText
relativeLayout.addView(ed, layoutParams);
//设置布局
setContentView(relativeLayout);
}
}

自定义的EditText控件：
[html] www.2cto.com
package com.mrzhu.edittest;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.widget.EditText;

public class EditTextTest extends EditText {

public EditTextTest(Context context) {
super(context);
}

public EditTextTest(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}

public EditTextTest(Context context, AttributeSet attrs) {
super(context, attrs);
}

@Override
protected void onDraw(Canvas canvas) {
Paint paint = new Paint();
paint.setTextSize(20);
paint.setColor(Color.GRAY);
canvas.drawText("输入提示文本:", 10, getHeight() / 2 + 5, paint);
super.onDraw(canvas);
}
}

main.xml:
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<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/linearlayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >

<Button
android:id="@+id/button2"
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="150dp"
android:onClick="click"
android:text="Button" />

</RelativeLayout>