Android5.0开发范例大全 读书笔记（三），android5.0范例

Android5.0开发范例大全 读书笔记（三），android5.0范例

（二）用户交互

2.14转发触摸事件

1.TouchDelegate很适合简单的触摸转发，它指定任意的矩形区域来向小视图转发触摸事件，其缺点是每个被转发的事件都会转发到代理视图的中间位置

public class TouchDelegateLayout extends FrameLayout {
    public TouchDelegateLayout(Context context) {
        this(context, null);
    }

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

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

    private CheckBox mCheckBox;

    private void init(Context context) {
        mCheckBox = new CheckBox(context);
        mCheckBox.setText("tap anywhere");
        addView(mCheckBox, new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, Gravity.CENTER));
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        if (w != oldw || h != oldh) {
            Rect rect = new Rect(0, 0, w, h);
            TouchDelegate touchDelegate = new TouchDelegate(rect, mCheckBox);
            setTouchDelegate(touchDelegate);
        }
    }
}

 2.自定义触摸转发

  在onTouch中改变event事件信息

 @Override
    public boolean onTouch(View v, MotionEvent event) {
        event.setLocation(event.getX(),event.getY()/2);
        scrollView.dispatchTouchEvent(event);
        return true;

    }

2.15阻止触摸窃贼

1. 调用requestDisallowTouchIntercept()方法，请求父控件不要截获当前的触摸事件

2.16创建拖放视图

拖1.使用DragShadowBuilder构造被拖动视图的外观

2.调用View.startDrag()开启拖动

 @Override
    public boolean onLongClick(View v) {
        View.DragShadowBuilder shadowBuilder=new View.DragShadowBuilder(v);
        v.startDrag(null, shadowBuilder, ((ImageView) v).getDrawable(),0);
        return true;
    }

放

3.通过OnDragListener.onDrag()监听拖动的事件，可以自定义一个视图实现listener接口，以下为核心代码

 @Override
    public boolean onDrag(View v, DragEvent event) {
        PropertyValuesHolder pvhX, pvhY;
        switch (event.getAction()) {
            case DragEvent.ACTION_DRAG_STARTED:
                pvhX = PropertyValuesHolder.ofFloat("scaleX", 0.5f);
                pvhY = PropertyValuesHolder.ofFloat("scaleY", 0.5f);
                ObjectAnimator.ofPropertyValuesHolder(this, pvhX, pvhY).start();
                setImageDrawable(null);
                mDropped = false;
                break;
            case DragEvent.ACTION_DRAG_ENDED:
                if (!mDropped) {
                    pvhX = PropertyValuesHolder.ofFloat("scaleX", 1f);
                    pvhY = PropertyValuesHolder.ofFloat("scaleY", 1f);
                    ObjectAnimator.ofPropertyValuesHolder(this, pvhX, pvhY).start();
                    mDropped = false;
                }
                break;
            case DragEvent.ACTION_DRAG_ENTERED:
                pvhX = PropertyValuesHolder.ofFloat("scaleX", 0.75f);
                pvhY = PropertyValuesHolder.ofFloat("scaleY", 0.75f);
                ObjectAnimator.ofPropertyValuesHolder(this, pvhX, pvhY).start();
                break;
            case DragEvent.ACTION_DRAG_EXITED:
                pvhX = PropertyValuesHolder.ofFloat("scaleX", 0.5f);
                pvhY = PropertyValuesHolder.ofFloat("scaleY", 0.5f);
                ObjectAnimator.ofPropertyValuesHolder(this, pvhX, pvhY).start();
                break;
            case DragEvent.ACTION_DROP:
                Keyframe frame0=Keyframe.ofFloat(0f,0.75f);
                Keyframe frame1=Keyframe.ofFloat(0.5f,0f);
                Keyframe frame2=Keyframe.ofFloat(1f,0.75f);
                pvhX = PropertyValuesHolder.ofKeyframe("scaleX", frame0,frame1,frame2);
                pvhY = PropertyValuesHolder.ofKeyframe("scaleY", frame0, frame1, frame2);
                ObjectAnimator.ofPropertyValuesHolder(this, pvhX, pvhY).start();
                setImageDrawable((Drawable) event.getLocalState());
                mDropped=true;
                break;
            default:
                return false;

        }
        return true;
    }

2.17构建导航Drawer

1.DrawerLayout只在Android支持库中提供，关键点在于设置gravity的属性

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <FrameLayout
        android:id="@+id/middle"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
    <ListView
        android:id="@+id/left"
        android:layout_width="240dp"
        android:layout_height="match_parent"
        android:layout_gravity="left"
        android:background="#555"/>
    <LinearLayout
        android:id="@+id/right"
        android:layout_width="240dp"
        android:layout_height="match_parent"
        android:layout_gravity="right"
        android:orientation="vertical"
        android:background="#ccc">
        <TextView
            android:layout_width="wrap_content"
            android: