xml佈局:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:orientation="vertical"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <RelativeLayout
        android:background="#f00"
        android:layout_width="match_parent"
        android:layout_height="200dp">

        <com.ww.wangwei.practice_week01.WaveView
            android:id="@+id/waveview"
            android:layout_width="match_parent"
            android:layout_height="40px"
            android:layout_alignParentBottom="true"/>

        <ImageView
            android:id="@+id/image"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_centerHorizontal="true"
            android:src="@mipmap/ic_launcher"/>

    </RelativeLayout>

</LinearLayout>
 

首先 新建一個class WaveView 繼承View

public class WaveView extends View {

    private static final String TAG = "WaveView";
    private Paint paint1;
    private Paint paint2;
    private PaintFlagsDrawFilter drawFilter;
    private float fai = 0;
    private Path path1;
    private Path path2;

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

    public WaveView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public WaveView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    //波動浮動監聽
    public interface OnWaveChangeListener {
        void onchange(float y);
    }

    private OnWaveChangeListener listener;

    public void setOnWaveChangeListener(OnWaveChangeListener listener) {
        this.listener = listener;
    }

    private void init() {
        paint1 = new Paint();
        paint1.setColor(Color.WHITE);
        paint1.setStyle(Paint.Style.FILL);
        paint1.setAntiAlias(true);
        paint1.setStrokeWidth(5);

        paint2 = new Paint();
        paint2.setColor(Color.WHITE);
        paint2.setAntiAlias(true);
        paint2.setStrokeWidth(5);
        paint2.setAlpha(60);

        path1 = new Path();
        path2 = new Path();

        drawFilter = new PaintFlagsDrawFilter(0, Paint.FILTER_BITMAP_FLAG | Paint.ANTI_ALIAS_FLAG);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        double v = 2 * Math.PI / getMeasuredWidth();

        canvas.setDrawFilter(drawFilter);

        fai -= 0.1f;

        int i = getMeasuredHeight() / 2;

        path1.reset();
        path2.reset();

        //起始點在左下角
        path1.moveTo(getLeft(), getBottom());
        path2.moveTo(getLeft(), getBottom());

        //從最左側開始 畫到最右側 每20px畫一條線
        for (int x = 0; x <= getMeasuredWidth(); x += 20) {

            float y1 = i * (float) Math.sin(v * x + fai) + i;
            float y2 = -i * (float) Math.sin(v * x + fai) + i;

            if (x > getMeasuredWidth() / 2 - 10 && x < getMeasuredWidth() / 2 + 10) {
                listener.onchange(y2);
            }

            path1.lineTo(x, y1);
            path2.lineTo(x, y2);
        }

        //終止點在右下角
        path1.lineTo(getWidth(), getBottom());
        path2.lineTo(getWidth(), getBottom());

        canvas.drawPath(path1, paint1);
        canvas.drawPath(path2, paint2);

        postInvalidateDelayed(50);
    }
}
 

java程式碼:

public class MainActivity extends AppCompatActivity {

private static final String TAG = "MainActivity";
private WaveView waveView;
private ImageView image;

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

    waveView = (WaveView) findViewById(R.id.waveview);
    image = (ImageView) findViewById(R.id.image);

    WaveView.OnWaveChangeListener listener = new WaveView.OnWaveChangeListener() {

        @Override
        public void onchange(float y) {
            RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) image.getLayoutParams();
            layoutParams.setMargins(0, 0, 0, (int) y);
            image.setLayoutParams(layoutParams);
        }
    };
    waveView.setOnWaveChangeListener(listener);
    }
}