1. 程式人生 > >Android自定義控制元件之仿汽車之家下拉重新整理

Android自定義控制元件之仿汽車之家下拉重新整理

這裡寫圖片描述
關於下拉重新整理的實現原理我在上篇文章Android自定義控制元件之仿美團下拉重新整理中已經詳細介紹過了,這篇文章主要介紹錶盤的動畫實現原理

汽車之家的下拉重新整理分為三個狀態:
第一個狀態為下拉重新整理狀態(pull to refresh),在這個狀態下是一個錶盤隨著下拉的距離動態改變指標的角度
第二個狀態為放開重新整理狀態(release to refresh),在這個狀態下是指標角度變化的一個動畫

第一個狀態的實現:

這裡寫圖片描述
這個效果我們使用自定義View來實現,我們從汽車之家apk中拿到下拉重新整理所用到的兩張圖片:
這裡寫圖片描述
這裡寫圖片描述
我們將第一張圖片畫在畫布上作為背景,接著我們根據當前進度值來動態旋轉畫布,然後再將第二章圖片畫在畫布上,我們看到錶針的旋轉實則是畫布在旋轉。

 @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
            //現將第一張圖片畫在畫布上
            canvas.drawBitmap(finalBackGroundBitmap,0,0,null);
            //旋轉畫布
            canvas.rotate(mCurrentProgress*2.7f,x/2,y/2);
            //將第二張圖片畫在旋轉後的畫布上
            canvas.drawBitmap(finalPointerBitmap, 0
, 0, null); }

自定義View的完整程式碼如下:

/**
 * Created by zhangqi on 15/10/17.
 */
public class AutoHome extends View{
    private Bitmap backGroundBitmap;
    public Bitmap pointerBitmap;
    private int x;
    private int y;
    private Bitmap finalBackGroundBitmap;
    private Bitmap finalPointerBitmap;
    private
float mCurrentProgress; public AutoHome(Context context) { super(context); init(context); } public AutoHome(Context context, AttributeSet attrs) { super(context, attrs); init(context); } public AutoHome(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(context); } private void init(Context context) { backGroundBitmap = Bitmap.createBitmap(BitmapFactory.decodeResource(context.getResources(), R.drawable.load_icon_dial2x)); pointerBitmap = Bitmap.createBitmap(BitmapFactory.decodeResource(context.getResources(), R.drawable.load_icon_pointer2x)); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { setMeasuredDimension(measureWidth(widthMeasureSpec),measureWidth(heightMeasureSpec)); x = getMeasuredWidth(); y = getMeasuredHeight(); finalBackGroundBitmap = Bitmap.createScaledBitmap(backGroundBitmap, x, y, false); finalPointerBitmap = Bitmap.createScaledBitmap(pointerBitmap, x, y, false); } private int measureWidth(int widMeasureSpec){ int result = 0; int size = MeasureSpec.getSize(widMeasureSpec); int mode = MeasureSpec.getMode(widMeasureSpec); if (mode == MeasureSpec.EXACTLY){ result = size; }else{ result = backGroundBitmap.getWidth(); if (mode == MeasureSpec.AT_MOST){ result = Math.min(result,size); } } return result; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); canvas.drawBitmap(finalBackGroundBitmap,0,0,null); canvas.rotate(mCurrentProgress*2.7f,x/2,y/2); canvas.drawBitmap(finalPointerBitmap, 0, 0, null); } public void setCurrentProgress(float progress){ mCurrentProgress = progress*100; } }

接著我們在Activity中用SeekBar來模擬一個進度值,從而傳遞給我們自定義View

public class MainActivity extends AppCompatActivity {
    private SeekBar mSeekBar;
    private AutoHome mAutoHome;
    private float mCurrentProgress;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mSeekBar = (SeekBar) findViewById(R.id.seekbar);
        mAutoHome = (AutoHome) findViewById(R.id.autohome);

        mSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
                mCurrentProgress = (float)seekBar.getProgress()/(float)seekBar.getMax();
                mAutoHome.setCurrentProgress(mCurrentProgress);
                mAutoHome.invalidate();
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });
    }

第二個狀態的實現:

第二個狀態是錶針在執行一個旋轉的動畫,我們可以將錶針寫成一個自定義View,然後錶盤作為背景圖片,然後錶針View來執行rotate動畫即可

/**
 * Created by zhangqi on 15/10/27.
 */
public class PointerView extends View {
    private int x;
    private int y;
    private Bitmap finalPointerBitmap;
    private Bitmap pointerBitmap;
    public PointerView(Context context) {
        super(context);
        init();
    }

    public PointerView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

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

    private void init() {
        pointerBitmap = Bitmap.createBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.load_icon_pointer2x));
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(measureWidth(widthMeasureSpec),measureWidth(heightMeasureSpec));
        x = getMeasuredWidth();
        y = getMeasuredHeight();
        finalPointerBitmap = Bitmap.createScaledBitmap(pointerBitmap, x, y, false);
    }
    private int measureWidth(int widMeasureSpec){
        int result = 0;
        int size = MeasureSpec.getSize(widMeasureSpec);
        int mode = MeasureSpec.getMode(widMeasureSpec);
        if (mode == MeasureSpec.EXACTLY){
            result = size;
        }else{
            result = pointerBitmap.getWidth();
            if (mode == MeasureSpec.AT_MOST){
                result = Math.min(result,size);
            }
        }
        return result;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //目的是讓錶針初始位置為270度!
        canvas.rotate(270,x/2,y/2);
        canvas.drawBitmap(finalPointerBitmap,0,0,null);
    }
}

然後我們在xml檔案中這樣寫:

 <FrameLayout
    android:id="@+id/anim_container"
    android:layout_width="45dp"
    android:layout_height="45dp"
    android:layout_margin="15dp"
    android:visibility="gone" >

    <com.zhangqi.autohomerefreshlistview.PointerView
        android:id="@+id/anim_pointer"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/load_icon_dial2x" />
    </FrameLayout>

這樣就將錶盤作為背景了,我們可以操作錶針來執行rotate動畫

<?xml version="1.0" encoding="utf-8"?>
<rotate xmlns:android="http://schemas.android.com/apk/res/android"
    android:fromDegrees="0"
    android:toDegrees="-150"
    android:pivotY="50%"
    android:pivotX="50%"
    android:duration="1000"
    android:repeatCount="infinite"
    android:repeatMode="reverse"

    >
</rotate>
mAutoHomeAnim = (PointerView) headerView.findViewById(R.id.anim_pointer);
animation = AnimationUtils.loadAnimation(context, R.anim.pointer_rotate);
//執行動畫
mAutoHomeAnim.startAnimation(animation);

在listview中

由於下拉重新整理核心程式碼和美團下拉重新整理是一樣的,這裡我只擷取不一樣的部分

private void changeHeaderByState(int state){
        switch (state) {
        case DONE:
            headerView.setPadding(0, -headerViewHeight, 0, 0);
            //第一狀態的view顯示出來
            mAutoHome.setVisibility(View.VISIBLE);
            //先停止一下第二階段view的動畫
            mAutoHomeAnim.clearAnimation();
            //將第二階段view隱藏起來
            mAnimContainer.setVisibility(View.GONE);
            break;
        case RELEASE_TO_REFRESH:
            tv_pull_to_refresh.setText("放開重新整理");

            break;
        case PULL_TO_REFRESH:
            tv_pull_to_refresh.setText("下拉重新整理");
            //第一狀態view顯示出來
            mAutoHome.setVisibility(View.VISIBLE);
            //停止第二階段動畫
            mAutoHomeAnim.clearAnimation();
            //將第二階段view隱藏
            mAnimContainer.setVisibility(View.GONE);
            break;
        case REFRESHING:
            tv_pull_to_refresh.setText("正在重新整理");
            //將第一階段view隱藏
            mAutoHome.setVisibility(View.GONE);
            //將第二階段view顯示出來
            mAnimContainer.setVisibility(View.VISIBLE);
            //先停止第二階段動畫
            mAutoHomeAnim.clearAnimation();
            //啟動第二階段動畫
            mAutoHomeAnim.startAnimation(animation);
            break;
        default:
            break;
        }
    }

完整程式碼:

大家可以到我的GitHub上下載