仿天猫热点,淘宝头条向上自动滚动的textview

先贴出效果图:



实现思路:

自定义TextSwitcher,并在里边添加两个动画分别是向上出的和向上进.

使用:

scrollTextView.next();//跳向下一个  在这句话之后必须紧跟着scrollTextView.setText("这是第" + count + "次滚动");来设置内容

下面是源码:

首先先给scrollTextView的代码:

<span style="font-size:14px;">public class ScrollTextView extends TextSwitcher implements
ViewSwitcher.ViewFactory {

private Context context;

// inAnimation,outAnimation分别构成翻页的进出动画
private ScrollAnimation inAnimation;
private ScrollAnimation outAnimation;

public ScrollTextView(Context context) {
this(context, null);
}

public ScrollTextView(Context context, AttributeSet attrs) {
super(context, attrs);
//将获取自定义textSize的值，如果没有，则使用默认的值，15。
TypedArray typedArray = context.obtainStyledAttributes(attrs,
new int[] { 0x7f010000 });
typedArray.recycle();
this.context = context;
init();
}

private void init() {
setFactory(this);//创建两个view
inAnimation = createAnim(-90, 0, true, true);
outAnimation = createAnim(0, 90, false, true);
setInAnimation(inAnimation);
setOutAnimation(outAnimation);

}

private ScrollAnimation createAnim(float start, float end, boolean turnIn,
boolean turnUp) {
final ScrollAnimation rotation = new ScrollAnimation(start, end,
turnIn, turnUp);
rotation.setDuration(800);
rotation.setFillAfter(false);
rotation.setInterpolator(new AccelerateInterpolator());

return rotation;
}

/**
* 这里返回的TextView，就是我们看到的View
*/
@Override
public View makeView() {
TextView textView = new TextView(context);
textView.setGravity(Gravity.LEFT);
textView.setPadding(0, 6, 0, 6);
textView.setTextSize(12);
textView.setGravity(Gravity.CENTER_VERTICAL);// gravity center_vertical
textView.setText("");
textView.setSingleLine(true);
textView.setEllipsize(TruncateAt.END);
return textView;
}

public void next() {
if (getInAnimation() != inAnimation) {
setInAnimation(inAnimation);
}
if (getOutAnimation() != outAnimation) {
setOutAnimation(outAnimation);
}
}

class ScrollAnimation extends Animation {
private final float mFromDegrees;
private final float mToDegrees;
private float mCenterX;
private float mCenterY;
private final boolean mTurnIn;
private final boolean mTurnUp;
private Camera mCamera;

public ScrollAnimation(float fromDegrees, float toDegrees,
boolean turnIn, boolean turnUp) {
mFromDegrees = fromDegrees;
mToDegrees = toDegrees;
mTurnIn = turnIn;
mTurnUp = turnUp;
}

@Override
public void initialize(int width, int height, int parentWidth,
int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
mCamera = new Camera();
mCenterY = getHeight() / 2;
mCenterX = getWidth() / 2;
}

@Override
protected void applyTransformation(float interpolatedTime,
Transformation t) {
final float fromDegrees = mFromDegrees;
float degrees = fromDegrees
+ ((mToDegrees - fromDegrees) * interpolatedTime);

final float centerX = mCenterX;
final float centerY = mCenterY;
final Camera camera = mCamera;
final int derection = mTurnUp ? 1 : -1;

final Matrix matrix = t.getMatrix();

camera.save();
if (mTurnIn) {
camera.translate(0.0f, derection * mCenterY
* (interpolatedTime - 1.0f), 0.0f);
} else {
camera.translate(0.0f, derection * mCenterY
* (interpolatedTime), 0.0f);
}
camera.getMatrix(matrix);
camera.restore();

matrix.preTranslate(-centerX, -centerY);
matrix.postTranslate(centerX, centerY);
}
}
}</span>

接下来就是使用了  使用起来非常简单

布局文件

<span style="font-size:14px;"><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:auto3d="http://schemas.android.com/apk/res/com.example.scrolltextview"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<com.example.scrolltextview.ScrollTextView
android:id="@+id/switcher02"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:background="#ff669900"
android:paddingBottom="5dp"
android:paddingTop="5dp"
auto3d:textSize="30sp" >
</com.example.scrolltextview.ScrollTextView>

</RelativeLayout></span>

MainActivity中,现在oncreat方法中先给一个初始值    然后在子线程中给个1秒发一个空消息  在主线程中收到消息后跳到下一个并设置文字

<span style="font-size:14px;">public class MainActivity extends Activity {

private ScrollTextView scrollTextView;
private static int count = 0;
private boolean isContinue;
private Thread myThread;

private Handler handler = new Handler() {
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case 0:
scrollTextView.next();
count++;
scrollTextView.setText("这是第" + count + "次滚动");
break;
default:
break;
}
};
};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
}

private void init() {
scrollTextView = (ScrollTextView) findViewById(R.id.switcher02);
scrollTextView.setText("初始值");// 设置初始值
isContinue = true;
myThread = new Thread() {
public void run() {
while (isContinue) {
SystemClock.sleep(2000);
handler.sendEmptyMessage(0);// 每隔一秒 发一个空消息 滚动一次
}
};
};
myThread.start();
}

/**
* 在销毁的时候干掉线程
*/
@Override
protected void onDestroy() {
super.onDestroy();
isContinue = false;
if (myThread != null && myThread.isAlive()) {
myThread.interrupt();
}
}
}</span>

点击这里下载源码