Android界面编程之七 第六组UI组件：ViewAnimator及其子类

ViewAnimator是一个基类，它继承了FrameLayout，可以将多个View组件 叠在一起；可在切换View时表现动画效果

ViewAnimator 支持的常见XML属性有：

android:animateFistView

显示第一个View组件时是否显示动画

android:inAnimation

设置ViewAnimator显示组件时使用的动画

android:outAnimation

设置ViewAnimator隐藏组件时使用的动画

实际项目中一般使用ViewAnimator的几个子类

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2.7.1 ViewSwitcher的功能与用法

为了给ViewSwitcher添加多个组件，一般通过调用ViewSwitcher的SetFactory(ViewSwitcher.ViewFactory)方法为之设置ViewFactory，并由该ViewFactory为之创建View

示例代码：

publicclassMainActivity extends ActionBarActivity {

publicstaticfinalintNUMBER_PER_SCREEN= 12;

publicstaticclassDataItem {
publicString dataName;
publicDrawable drawable;
}

privateArrayList<DataItem> items = new ArrayList<DataItem>();
privateintscreenNo= -1;
privateintscreenCount;
ViewSwitcher switcher;
LayoutInflater inflater;

@Override
protectedvoidonCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
inflater= LayoutInflater.from(MainActivity.this);
for(inti = 0; i < 40; i++) {
String label = "" + i;
Drawable drawable = getResources().getDrawable(
R.drawable.ic_launcher);
DataItem item = new DataItem();
item.dataName= label;
item.drawable= drawable;
items.add(item);
}
screenCount= items.size() % NUMBER_PER_SCREEN == 0 ?items.size()
/ NUMBER_PER_SCREEN: items.size() / NUMBER_PER_SCREEN + 1;
switcher= (ViewSwitcher) findViewById(R.id.viewSwitcher);
switcher.setFactory(newViewFactory()
{
@Override
publicView makeView()
{
returninflater.inflate(R.layout.slideviewlist,null);
}
});
next(null);
}
publicvoidnext(View v)
{
if(screenNo< screenCount -1)
{
screenNo++;
switcher.setInAnimation(this, R.anim.slide_in_right);
switcher.setOutAnimation(this, R.anim.slide_out_left);
((GridView) switcher.getNextView()).setAdapter(adapter);
switcher.showNext();
}
}
publicvoidprev(View v)
{
if(screenNo> 0)
{
screenNo--;
switcher.setInAnimation(this, R.anim.slide_in_right);
switcher.setOutAnimation(this, R.anim.slide_out_left);
((GridView) switcher.getNextView()).setAdapter(adapter);
switcher.showPrevious();
}
}
privateBaseAdapter adapter = new BaseAdapter()
{
@Override
publicintgetCount()
{
if(screenNo== screenCount - 1
&& items.size() %NUMBER_PER_SCREEN!= 0)
{
returnitems.size() %NUMBER_PER_SCREEN;
}
returnNUMBER_PER_SCREEN;

}
@Override
publicDataItem getItem(intposition)
{
returnitems.get(screenNo* NUMBER_PER_SCREEN + position);
}
@Override
publiclonggetItemId(intposition)
{
returnposition;
}
@Override
publicView getView(intposition,
View convertView, ViewGroup parent)
{
View view = convertView;
if(convertView == null)
{
view = inflater.inflate(R.layout.labelicon,null);
}
ImageView imageView = (ImageView)
view.findViewById(R.id.imageview);
imageView.setImageDrawable (getItem(position).drawable);
TextView textView = (TextView)
view.findViewById(R.id.textview);
textView.setText(getItem(position).dataName);
returnview;
}

};

}

xml代码：

main.xml

<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <ImageView
        android:id="@+id/iamge"
        android:layout_width="match_parent"
        android:layout_height="240px"
        android:src="@drawable/lijiang"
        />
    <RatingBar
        android:id="@+id/rating"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:numStars="5"
        android:max="255"
        android:progress="255"
        android:stepSize="0.5"
        />
</LinearLayout>

slideviewlist.xml

<?xmlversion="1.0"encoding="utf-8"?>
<GridView
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:numColumns="4"
  android:layout_height="match_parent">
   

</GridView>

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2.7.2 图像切换器的功能与用法 ImagesSwitcher

ImageSwitcher继承了ViewSwitcher，并重写了ViewSwitcher的showNext()、showPrevious()方法，因此ImageSwitcher使用起来更加简单。使用ImageSwitcher只要如下两步即可：

1.ImageSwitcher提供一个ViewFactory，该ViewFactory生成View组件必须是ImageView

2.需要切换图片时，只要调用ImageSwitcher的setImageDrawable(Drawable drawable)、setImageResource(int reside) 和setImageURI(Uri uri)方法更换图片即可

示例代码：

publicclassMainActivity extends ActionBarActivity {

int[]imageIds= new int[]
{
R.drawable.bomb5, R.drawable.bomb6, R.drawable.bomb7
, R.drawable.bomb8, R.drawable.bomb9, R.drawable.bomb10
, R.drawable.bomb11, R.drawable.bomb12, R.drawable.bomb13
, R.drawable.bomb14, R.drawable.bomb15, R.drawable.bomb16
};
ImageSwitcher switcher;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        List<Map<String, Object>> listItems =
        newArrayList<Map<String, Object>>();
        for(inti = 0; i < imageIds.length; i++)
        {
        Map<String, Object> listItem = new HashMap<String, Object>();
        listItem.put("image",imageIds[i]);
        listItems.add(listItem);
        }
        switcher = (ImageSwitcher) findViewById(R.id.switcher);
        switcher.setFactory(newViewFactory()
        {
        @Override
        publicView makeView()
        {
        ImageView imageView = new ImageView(MainActivity.this);
        imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
        imageView.setLayoutParams(newImageSwitcher.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT));
        returnimageView;
        }
        });
        SimpleAdapter simpleAdapter = new SimpleAdapter(this, listItems,
        R.layout.cell,newString[]{"iamge"},
        newint[]{R.id.image1});
        GridView grid = (GridView) findViewById(R.id.grid01);
        grid.setAdapter(simpleAdapter);
        grid.setOnItemSelectedListener(newOnItemSelectedListener()
        {
        @Override
        publicvoidonItemSelected(AdapterView<?> parent, View view,intposition, long id)
        {
        switcher.setImageResource(imageIds[position]);
        }
        @Override
        publicvoidonNothingSelected(AdapterView<?> parent)
        {
       
        }
        });
        grid.setOnItemClickListener(newOnItemClickListener()
        {
        @Override
        publicvoidonItemClick(AdapterView<?> parent, View view,intposition, long id)
        {
        switcher.setImageResource(imageIds[position]);
        }
        });

    }

}

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2.7.3 文本切换器 TextSwitcher

可指定文本切换时的动画效果

实例代码：

publicclassMainActivity extends ActionBarActivity {

TextSwitcher textSwitcher;
String[] strs = new String[]
{
"crazy it",
"crazy world",
"crazy programmer"

};
intcurStr;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textSwitcher = (TextSwitcher) findViewById(R.id.textSwitcher);
        textSwitcher.setFactory(newViewSwitcher.ViewFactory() {

@Override
publicView makeView() {
//TODOAuto-generated method stub
TextView tv = new TextView(MainActivity.this);
tv.setTextSize(40);
tv.setTextColor(Color.MAGENTA);
returntv;
// return null;
}
});
    }
        public void next(View source)
        {
        textSwitcher.setText(strs[curStr++ % strs.length]);

        }

}

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2.7.4 ViewFlipper

ViewFlipper可以指定与AdapterViewFlipper相同的XML属性；

ViewFlipper需要开发者通过addView(View v) 添加多个View，而AdapterViewFlipper则只要传入一个Adapter（Adapter负责提供多个View）。