自定义View-view的执行方法

  @SuppressLint("HandlerLeak")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.e("tag","onCreate");
        setContentView(R.layout.activity_main);
}

public class DemoView extends View {
    public DemoView(Context context) {
        super(context);
        Log.i("tag", "----  public DemoView(Context context) ----");

    }

    public DemoView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        Log.i("tag", "----  public DemoView(Context context,AttributeSet attrs) ----");
    }

    public DemoView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        Log.i("tag", "----  public DemoView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) ----");
    }
    /**
     * 使用布局文件XML创建CustomView时，在xml文件加载完成后调用这个方法
     */
    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        Log.i("tag", "----  onFinishInflate() ----");
    }

    /**
     * CustomView的大小发生改变时调用这个方法
     *
     * @param w
     * @param h
     * @param oldw
     * @param oldh
     */
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        Log.i("tag", "----  onSizeChanged = " + " w = " + w + "  h = " + h + "  oldW = " + oldw + "  oldH = " + oldw);
    }

    /**
     * 在画布上面绘制
     *
     * @param canvas
     */
    @Override
    protected void dispatchDraw(Canvas canvas) {
        super.dispatchDraw(canvas);
        Log.i("tag", "----  dispatchDraw = ");
    }

    /**
     * 绘制CustomView时调用
     *
     * @param canvas
     */
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Log.i("tag", "----  onDraw ----");
    }

    /**
     * 测量CustomView的大小
     *
     * @param widthMeasureSpec
     * @param heightMeasureSpec
     */
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        Log.i("tag", "----  onMeasure ----");
    }

    /**
     * 将CustomView放置到父容器中去
     *
     * @param changed
     * @param left
     * @param top
     * @param right
     * @param bottom
     */
    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        Log.i("tag", "----  onLayout ----");
    }


    /**
     * 将CustomView依附到Window中
     */
    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        Log.i("tag", "----  onAttachedToWindow ----");
    }

    /**
     * 当手机屏幕从横屏和竖屏 相互转化时调用
     *
     * @param newConfig
     */
    @Override
    protected void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        Log.i("tag", "----  onConfigurationChanged ----");
    }

    @Override
    public void requestLayout() {
        super.requestLayout();
        Log.i("tag", "----  requestLayout ----");
    }

    @Override
    public void invalidate() {
        super.invalidate();
        Log.i("tag", "----  invalidate ----");
    }
}

<?xml version="1.0" encoding="utf-8"?>
<com.example.handlerdemo.DemoView 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:layout_height="match_parent"
    tools:context=".MainActivity"
    android:id="@+id/layout">

<!--    <TextView-->
<!--        android:layout_width="wrap_content"-->
<!--        android:layout_height="wrap_content"-->
<!--        android:text="Hello World!"-->
<!--        app:layout_constraintBottom_toBottomOf="parent"-->
<!--        app:layout_constraintLeft_toLeftOf="parent"-->
<!--        app:layout_constraintRight_toRightOf="parent"-->
<!--        app:layout_constraintTop_toTopOf="parent" />-->

</com.example.handlerdemo.DemoView>

首次打开activity:

 activity处于onPause的时候：

 重新在onResume: