首先創建一個TVOffAnimation繼承於Animation:
- import android.graphics.Matrix;
- import android.view.animation.AccelerateDecelerateInterpolator;
- import android.view.animation.Animation;
- import android.view.animation.Transformation;
- public class TVOffAnimation extends Animation {
- private int halfWidth;
- private int halfHeight;
- @Override
- public void initialize(int width, int height, int parentWidth,
- int parentHeight) {
- super.initialize(width, height, parentWidth, parentHeight);
- setDuration(500);
- setFillAfter(true);
- //保存View的中心點
- halfWidth = width / 2;
- halfHeight = height / 2;
- setInterpolator(new AccelerateDecelerateInterpolator());
- }
- @Override
- protected void applyTransformation(float interpolatedTime, Transformation t) {
- final Matrix matrix = t.getMatrix();
- if (interpolatedTime < 0.8) {
- matrix.preScale(1+0.625f*interpolatedTime, 1-interpolatedTime/0.8f+0.01f,halfWidth,halfHeight);
- }else{
- matrix.preScale(7.5f*(1-interpolatedTime),0.01f,halfWidth,halfHeight);
- }
- }
- }
interpolatedTime表示的是當前動畫的間隔時間 範圍是0-1
那麼橫向來講前80%的時間我們要橫向拉伸到150%,縱向是直接減小,最後只留一條線。
後20%的時間裏我們要橫向從150%壓縮至0%,縱向保持不變就好了,當橫向爲0的時候就全部消失了。
可能大家對於1+0.625f*interpolatedTime, 1-interpolatedTime/0.8f+0.01f,7.5f*(1-interpolatedTime),0.01f 這4個值比較疑惑,其實很簡單,這是一個一次函數的函數值。
然後在activity中直接可以用了
- View img = findViewById(R.id.imageView);
- button.setOnClickListener(new OnClickListener() {
- @Override
- public void onClick(View v) {
- img.startAnimation(new TVOffAnimation());
- }
- });