Android ScrollView(画轴视图）

Android ScrollView(卷轴视图）
<?xml version=”1.0″ encoding=”utf-8″?>
<ScrollView xmlns:android=”http://schemas.android.com/apk/res/android”
android:id=”@+id/ScrollView01″
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:scrollbars=”none”>


<LinearLayout
android:id=”@+id/layout”
android:orientation=”vertical”
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
>


<TextView
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:text=”TextView0″
/>


<Button
android:id=”@+id/Button01″
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:text=”Button”/>


</LinearLayout>


</ScrollView>

package eoe.Demo;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ScrollView;
import android.widget.TextView;

public class ScrollView01 extends Activity {
private LinearLayout mLayout;
private ScrollView mScrollView;
private final Handler mHandler=new Handler();
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);


//线性布局
mLayout=(LinearLayout)findViewById(R.id.layout);
mScrollView=(ScrollView)findViewById(R.id.ScrollView01);


Button button=(Button)findViewById(R.id.Button01);


button.setOnClickListener(mClickListener);


//改变默认焦点切换
button.setOnKeyListener(mAddButtonKeyListener);
}


//当点击按钮时，增加一个TextView和Button
private Button.OnClickListener mClickListener=new Button.OnClickListener(){
private int mIndex=1;


@Override
public void onClick(View arg0){
TextView mTextView=new TextView(ScrollView01.this);
mTextView.setText(“Text View”+mIndex);
LinearLayout.LayoutParams p=new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.FILL_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT
);


//增加一个TextView到线性布局中
mLayout.addView(mTextView,p);
Button mButtonView=new Button(ScrollView01.this);
mButtonView.setText(“Button”+mIndex++);
mLayout.addView(mButtonView,p);


//改变默认焦点切换
mButtonView.setOnKeyListener(mNewButtonKeyListener);


//投递一个消息进行滚动
mHandler.post(mScrollToBottom);
}
};


//新建后滚动到最后
private Runnable mScrollToBottom=new Runnable(){


public void run(){
int off=mLayout.getMeasuredHeight()-mScrollView.getHeight();
if(off>0){
mScrollView.scrollTo(0, off);
}
}
};



//滚动到最后回到头
private View.OnKeyListener mNewButtonKeyListener=new View.OnKeyListener(){


@Override
public boolean onKey(View v, int keyCode, KeyEvent event){


if(keyCode==KeyEvent.KEYCODE_DPAD_DOWN&&
v==mLayout.getChildAt(mLayout.getChildCount()-1)){


findViewById(R.id.Button01).requestFocus();
return true;
}
// TODO Auto-generated method stub
return false;
}
};


//滚动到头回到尾
private View.OnKeyListener mAddButtonKeyListener=new Button.OnKeyListener(){


@Override
public boolean onKey(View v,int keyCode,KeyEvent event){
View viewToFoucus=null;
if(event.getAction()==KeyEvent.ACTION_DOWN)
{
int iCount=mLayout.getChildCount();
switch(keyCode)
{
case KeyEvent.KEYCODE_DPAD_UP:
if(iCount>0)
{
viewToFoucus=mLayout.getChildAt(iCount-1);
}
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
if(iCount 111. {
viewToFoucus=mLayout.getChildAt(iCount+1);
}
break;
default:
break;
}
}
if(viewToFoucus!=null)
{
viewToFoucus.requestFocus();
return true;
}
else
{
return false;
}
}
};
}

上面的代码主要用到了KeyEvent，View，ScrollView这三个。我们用到先行布局来呈现出Button，mScrollView，我们在设置一个private的Button监听，我们在设置一下textview，最后我们就用一个run()方法，当我们的效果滚到最后时，我们要判断一下怎么样才能往回滚。我们在判断一下当滚到头时在滚到最后部，这样来回循环。上面我解析的大家要是不明白的就回帖指出来，要是我解析不对的，就指出来，指出来以后我好改正。