Android stuido有android tv項目模闆，有一套規則，如果想開發TV版項目可以按照那個模闆來，不過那個模闆定制性太強。tv版app和其他app有一點不同，就是用遙控器進行操作，是以要想按照自己需求來開發，就要處理好焦點事件。
其實也不複雜，隻要繼承現有的控件，在onFocusChanged事件中，對自己的需求進行定制就可以了。提供幾個例子：
1.顯示圖檔的控件，預設加載預設圖檔，當獲得焦點以後，切換選中圖檔，失去焦點，切換預設圖檔
public class FocusImageView extends ImageButton
{
private int defaultImageResources = -;
private int focusImageResources = -;
public FocusImageView(Context context)
{
super(context);
}
public FocusImageView(Context context, AttributeSet attrs)
{
this(context, attrs, );
}
public FocusImageView(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
setAttributeSet(attrs);
}
@Override
protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect)
{
super.onFocusChanged(gainFocus, direction, previouslyFocusedRect);
if (gainFocus)
{
if (focusImageResources != -)
{
setBackgroundResource(focusImageResources);
}
}
else
{
if (defaultImageResources != -)
{
setBackgroundResource(defaultImageResources);
}
}
}
private void setAttributeSet(AttributeSet attrs)
{
if (attrs != null)
{
TypedArray typeArray = getContext().obtainStyledAttributes(attrs, R.styleable.FocusImageView);
defaultImageResources = typeArray.getResourceId(R.styleable.FocusImageView_defaultImageResources, -);
focusImageResources = typeArray.getResourceId(R.styleable.FocusImageView_focusImageResources, -);
if (defaultImageResources != -)
{
setBackgroundResource(defaultImageResources);
}
}
}
}
attrs.xml
<resources>
<declare-styleable name="FocusImageView">
<attr name="defaultImageResources" format="integer" />
<attr name="focusImageResources" format="integer" />
</declare-styleable>
</resources>
布局檔案引用：
<項目的包名.widget.focusview.FocusImageView
android:id="@+id/iv_wulianwang"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:defaultImageResources="@mipmap/wulianwangdefault"
app:focusImageResources="@mipmap/wulianwangselected">
</項目的包名.widget.focusview.FocusImageView>
當然，如果隻是在擷取焦點和失去焦點，切換圖檔，可以定義selector，在drawable下，定義一個selector
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@mipmap/bingliselected" android:state_focused="true" />
<item android:drawable="@mipmap/binglidefault" />
</selector>
然後在布局中調用
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="6dp"
android:focusable="true"
android:background="@drawable/focus_selector">
2.一個布局，内部控件獲得焦點，可以放大，失去焦點，内部控件可以縮小：
public class FocusRelativeLayout extends RelativeLayout {
private Animation scaleSmallAnimation;
private Animation scaleBigAnimation;
public FocusRelativeLayout(Context context) {
super(context);
}
public FocusRelativeLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public FocusRelativeLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) {
super.onFocusChanged(gainFocus, direction, previouslyFocusedRect);
if (gainFocus) {
zoomOut();
} else {
zoomIn();
}
}
private void zoomIn() {
if (scaleSmallAnimation == null) {
scaleSmallAnimation = AnimationUtils.loadAnimation(getContext(), R.anim.anim_scale_small);
}
startAnimation(scaleSmallAnimation);
}
private void zoomOut() {
if (scaleBigAnimation == null) {
scaleBigAnimation = AnimationUtils.loadAnimation(getContext(), R.anim.anim_scale_big);
}
startAnimation(scaleBigAnimation);
}
}
anim_scale_big.xml
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
android:fillAfter="true"
android:shareInterpolator="false">
<scale
android:duration="350"
android:fromXScale="1.0"
android:fromYScale="1.0"
android:interpolator="@android:anim/accelerate_decelerate_interpolator"
android:pivotX="50.0%"
android:pivotY="50.0%"
android:repeatCount="0"
android:toXScale="1.08"
android:toYScale="1.08" />
</set>
anim_scale_small.xml
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
android:fillAfter="true"
android:shareInterpolator="false">
<scale
android:duration="350"
android:fromXScale="1.08"
android:fromYScale="1.08"
android:interpolator="@android:anim/accelerate_decelerate_interpolator"
android:pivotX="50.0%"
android:pivotY="50.0%"
android:repeatCount="0"
android:toXScale="1.0"
android:toYScale="1.0" />
</set>
布局檔案引用：
<包名.view.FocusRelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#424242"
android:clipChildren="true"
android:focusable="true">
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:scaleType="fitXY"
android:src="@drawable/pic2"
android:layout_margin="5dp"/>
</包名.view.FocusRelativeLayout>
3.進入界面，讓某個控件擷取焦點
根據需求，可能對進入界面，首先選中哪個控件有需求，可以在布局檔案裡邊，使用
<requestFocus/>屬性
<包名.widget.focusview.FocusImageView
android:id="@+id/iv_bingli"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:defaultImageResources="@mipmap/binglidefault"
app:focusImageResources="@mipmap/bingliselected"
>
<requestFocus></requestFocus>
</包名.widget.focusview.FocusImageView>
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