android 落叶效果,安卓版落叶特效-canvas篇（一）
package net.cloudelevator.anim;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import java.util.ArrayList;
import java.util.List
public class MyCanvas extends View {
Paint paint;
Paint tpaint;
private int[] list = new int[192];
Handler handler = new Handler() {
@Override
public void handleMessage(@NonNull Message msg) {
switch (msg.what) {
case 1:
postInvalidate();
handler.sendEmptyMessageDelayed(1, 0);
break;
}
}
};
public MyCanvas(Context context) {
super(context);
for (int i = 0; i < 192; i++) {
list[i] = 1;
}
for (int j = 0; j < 100; j++) {
for (int i = 0; i < list.length; i++) {
if (list[i] > 758 + Math.random() * 1e4) {
list[i] = 0;
} else {
list[i] = list[i] + 10;
}
}
}
handler.sendEmptyMessageDelayed(1, 0);
}
public MyCanvas(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
for (int i = 0; i < 192; i++) {
list[i] = 1;
}
for (int j = 0; j < 100; j++) {
for (int i = 0; i < list.length; i++) {
if (list[i] > 758 + Math.random() * 1e4) {
list[i] = 0;
} else {
list[i] = list[i] + 10;
}
}
}
handler.sendEmptyMessageDelayed(1, 0);
}
public MyCanvas(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
for (int i = 0; i < 192; i++) {
list[i] = 1;
}
for (int j = 0; j < 100; j++) {
for (int i = 0; i < list.length; i++) {
if (list[i] > 758 + Math.random() * 1e4) {
list[i] = 0;
} else {
list[i] = list[i] + 10;
}
}
}
handler.sendEmptyMessageDelayed(1, 0);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
paint = new Paint();
tpaint = new Paint();
tpaint.setColor(Color.WHITE);
paint.setStrokeWidth(0);
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.bg);
canvas.drawBitmap(bitmap, 0, 0, paint);
for (int i = 0; i < list.length; i++) {
canvas.drawText("\uD83C\uDF42", i * 50, list[i], tpaint);
if (list[i] > 758 + Math.random() * 1e4) {
list[i] = 0;
} else {
list[i] = list[i] + 10;
}
}
}
}