向下和向上滚动时，循环视图，项目中的自定义视图会消失

Question

我有一个自定义视图消失的问题，我以编程方式创建并添加到项容器（RelativeLayout），当我向下和向上滚动时。它成功构建。

但是在滚动之后，我将此结果放在同一个项目中 - 一个空容器..

自定义视图

public class WaveFormView extends View {
Paint p;
Paint pTop;
Paint pBottom;
Rect rect;
Rect rect1;
int [] amplitudeArray;
int amplitudeArraySize;
int leftPointX;
int rightPointX;
int index;

boolean isPlay;

public static final int MAX_AMPLITUDE = 32;//was 1000
public static final int SIZE_OF_BAR_WAVE_FORM = 98;
public static final int BAR_SIZE_AND_INTERVAL = 5;


private static final float screenDensity = Utils.getDisplayDensity();

public WaveFormView(Context context, int [] amplitudeArray, boolean isPlay, int index) {
    super(context);
    p = new Paint();
    p.setColor(getResources().getColor(R.color.color_wave_from_grey));

    pTop = new Paint();
    pTop.setColor(getResources().getColor(R.color.color_wave_form_play_top));

    pBottom = new Paint();
    pBottom.setColor(getResources().getColor(R.color.color_wave_form_play_bottom));

    this.amplitudeArray = amplitudeArray;
    amplitudeArraySize = amplitudeArray.length;
    this.isPlay = isPlay;
    this.index = index;
}

@Override
protected void onDraw(Canvas canvas) {
    if(!isPlay){
        buildWaveForm(canvas);
    }
    else{
        buildWaveFormWhenPlay(canvas);
    }

}

private void buildWaveForm(Canvas canvas){

    int oneDp = (int) (1*screenDensity);
    int fourDp = (int) (4*screenDensity);
    int amplitudeDp = 0;
    int startBottomY = (int) (MAX_AMPLITUDE*screenDensity) + oneDp;
    p.setColor(getResources().getColor(R.color.color_wave_from_grey));
    for (int i = 0; i < amplitudeArraySize; i++){
        p.setStyle(Paint.Style.FILL_AND_STROKE);
        leftPointX += oneDp;
        rightPointX = leftPointX+fourDp;
        amplitudeDp  = (int) (amplitudeArray[i]*screenDensity);
        rect = new Rect(leftPointX, startBottomY, rightPointX, startBottomY + amplitudeDp);
        rect1 = new Rect(leftPointX, startBottomY-oneDp-amplitudeDp, rightPointX, startBottomY-oneDp);
        canvas.drawRect(rect, p);
        canvas.drawRect(rect1, p);
        leftPointX+=fourDp;
    }
}

private void buildWaveFormWhenPlay(Canvas canvas){
  ...}

适配器

public class PostTimeLineAdapter extends   
RecyclerView.Adapter<PostTimeLineHolder>   ... 
@Override
public void onBindViewHolder(final PostTimeLineHolder holder, final int position) { ...
holder.homeItemContainerWaveForm.addView(new       WaveFormView(context,bufferArray, false, -1));...}

持有人

public class PostTimeLineHolder extends RecyclerView.ViewHolder {

...
public RelativeLayout homeItemContainerWaveForm;


public PostTimeLineHolder(View itemView) {
    super(itemView);
    ...
    this.homeItemContainerWaveForm = (RelativeLayout) itemView.findViewById(R.id.home_item_sound_container_wave_forms);}}

感谢您的所有答案！

Answer 1

这种奇怪行为的原因是在运算符之后没有将这些参数归零：leftPointX和rightPointX，在方法buildWaveForm中。如果在operator for之后为它们设置了零，则方法buildWaveForm会精确地工作。