自定义View（波浪线实现代码）

一、Xml布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#80000f"
    tools:context="com.example.mickc.customviews.MainActivity">


    <FrameLayout
        android:layout_marginTop="200dp"
        android:layout_width="match_parent"
        android:background="#ff7403"
        android:layout_height="wrap_content">

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/image"
            android:layout_gravity="center_horizontal"
            android:src="@mipmap/ic_launcher"
            />

        <com.example.mickc.customviews.WaveView
            android:layout_marginTop="100dp"
            android:layout_width="match_parent"
            android:layout_height="15dp"
            android:id="@+id/waveView"
            />
    </FrameLayout>
</LinearLayout>

二、Activity中

public class MainActivity extends AppCompatActivity {

    private ImageView image;
    private WaveView waveView;
    private FrameLayout.LayoutParams lp;

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


    }

    private void initView() {
        image = (ImageView) findViewById(R.id.image);
        waveView = (WaveView) findViewById(R.id.waveView);

        lp = new FrameLayout.LayoutParams(-2,-2);

        lp.gravity=Gravity.CENTER;




        waveView.setAnimations(new WaveView.Animations() {
            @Override
            public void getY(float y) {
                lp.setMargins(0,-20,0, (int) (y+2));

                image.setLayoutParams(lp);
            }
        });

    }
}

三、工具类

public class WaveView extends View {

    private Paint paint;
    private Path path;
    float A=8f;
    float w;
    float k=0f;
    float f;
    float y;
    private Paint paint1;
    private Path path1;
    private float y1;


    public WaveView(Context context) {
        super(context);
        initView();
    }

    public WaveView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        initView();
    }

    public WaveView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initView();
    }

    private void initView() {
        //创建一个画笔
        paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(Color.WHITE);
        paint.setAntiAlias(true);//消除锯齿
        paint.setStyle(Paint.Style.FILL);
        path = new Path();

        //创建一个画笔
        paint1 = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint1.setColor(Color.WHITE);
        paint1.setAntiAlias(true);//消除锯齿
        paint1.setStyle(Paint.Style.FILL);
        paint1.setAlpha(80);
        path1 = new Path();

    }


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

        path.reset();
        path1.reset();

        /**
         *  y=Asin(ωx+φ)+k
         *  A—振幅越大，波形在y轴上最大与最小值的差值越大
         *  ω—角速度， 控制正弦周期(单位角度内震动的次数)
         *  φ—初相，反映在坐标系上则为图像的左右移动。这里通过不断改变φ,达到波浪移动效果
         *  k—偏距，反映在坐标系上则为图像的上移或下移。
         */

        path.moveTo(getLeft(),getBottom());
        path1.moveTo(getLeft(),getBottom());



        w= (float) (2*Math.PI/getWidth());
        f-=0.1f;


        for (int x = 0; x <=getWidth() ; x+=20) {
            y= (float) (A*Math.sin(w*x+f));
           y1 = (float) (A*Math.cos(w*x+f)+8);

            path.lineTo(x,y);
            path1.lineTo(x,y1);

            animations.getY(y);

        }

        path.lineTo(getRight(),getBottom());
        path1.lineTo(getRight(),getBottom());

        canvas.drawPath(path,paint);
        canvas.drawPath(path1,paint1);

        postInvalidateDelayed(20);


    }


    public void setAnimations(Animations animations) {
        this.animations = animations;
    }

    private  Animations animations;

    public interface  Animations{
        void getY(float y);
    }
}