如何使用removeView（）？

Question

我試圖以編程方式創建一個TextView並通過使用addView（）函數將其添加到布局中，但是卻遇到了運行時異常，即“指定的子代已經有一個父代。必須首先在該子代的父代上調用removeView（）” ”。 我已經看過所有有關此主題的問題，但仍然不明白如何以及何時使用removeView（）函數。

所以這是我的代碼：

import android.content.Intent;
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.View;
import android.widget.RelativeLayout;
import android.widget.RelativeLayout.LayoutParams;
import android.widget.TextView;
import java.util.Random;

public class MainActivity extends AppCompatActivity {

private int maxNumber = 6;
private Integer[] numbers = new Integer[maxNumber];
private Integer[] textSizes = new Integer[maxNumber];
private Integer[] colors = new Integer[8];
private Integer[] randomColors = new Integer[maxNumber];
private Integer[][] margins;
private LayoutParams params[];
private int maxValue = 1000;
private int maxSize = 50;
private int minSize = 15;
private int viewCount = 0;
private int startCount = 3;
private int layoutHeight;
private int layoutWidth;
private int score = 0;
private RelativeLayout layout;

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

    layout = (RelativeLayout) findViewById(R.id.layout);
    LayoutParams layoutParams = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
    layout.setLayoutParams(layoutParams);

    DisplayMetrics displayMetrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
    layoutHeight = displayMetrics.heightPixels;
    layoutWidth = displayMetrics.widthPixels;


    String[] colorsTxt = getApplicationContext().getResources().getStringArray(R.array.colors);
    for (int i = 0; i < colorsTxt.length; i++) {
        int newColor = Color.parseColor(colorsTxt[i]);
        colors[i] = newColor;
    }

    createTextView(3);
}

private void createTextView(int num)
{
    final TextView tv = new TextView(this);

    createProperties(num);

    eliminateSameRandoms();

    for(int i = viewCount; i < (viewCount + num); i++)
    {
        tv.setLayoutParams(params[i]);
        tv.setText(String.valueOf(numbers[i]));
        tv.setTextColor(randomColors[i]);
        tv.setTextSize(textSizes[i]);
        createListener(tv);
        layout.addView(tv);
    }
    viewCount += num;
}

private void createListener(final TextView textView)
{
    textView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (Integer.parseInt(String.valueOf(textView.getText())) == getBiggest()) {
                score++;
                if(viewCount == startCount * startCount) {
                    startCount++;
                    createTextView(startCount);
                }
                else {
                    createTextView(startCount);
                }
            } else {
                Intent i = new Intent(MainActivity.this, FailActivity.class);
                i.putExtra("score", score);
                startActivity(i);
            }
        }
    });

}

private int getBiggest()
{
    int max = 0;
    for(int i : numbers)
    {
        if(i > max)
        {
            max = i;
        }
    }
    return max;
}

private void createProperties(int num)
{
    createRandoms(num);
    createColors(num);
    createTextSizes(num);
    createMargins(num);
    createParams(num);
}

private void createRandoms(int numRandoms)
{
    for(int i = viewCount; i < (viewCount + numRandoms); i++)
    {
        numbers[i] = new Random().nextInt(maxValue);
    }
}

private void createParams(int numParams)
{
    params = new LayoutParams[numParams];
    for(int i = viewCount; i < (viewCount + numParams); i++)
    {
        params[i] = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        params[i].leftMargin = margins[i][0];
        params[i].topMargin = margins[i][1];
    }
}

private void createMargins(int numMargins)
{
    margins = new Integer[numMargins][2];
    for(int i = viewCount; i < (viewCount + numMargins); i++)
    {
        margins[i][0] = new Random().nextInt(layoutWidth - 40) + 20;
        margins[i][1] = new Random().nextInt(layoutHeight - 40) + 20;
    }
}

private void createTextSizes(int numTextSizes)
{
    for(int i = viewCount; i < (viewCount + numTextSizes); i++)
    {
        textSizes[i] = new Random().nextInt(maxSize - minSize) + minSize;
    }
}

private void createColors(int numColors)
{
    for(int i = viewCount; i < (viewCount + numColors); i++)
    {
        randomColors[i] = colors[new Random().nextInt(colors.length - 1)];
    }
}

private boolean inRange(int position, int other)
{
    int range = 60;
    return !(position - other < range && other - position < range);
}

private void eliminateSameRandoms()
{
    int numRandoms = viewCount;
    int i = 0;
    while(i < numRandoms)
    {
        for(int j = 0; j < numRandoms; j++)
        {
            Log.d("i: " , String.valueOf(i));
            Log.d("j: " , String.valueOf(j));
            if(j != (numRandoms - i))
            {
                while (numbers[j].equals(numbers[numRandoms - (i + 1)]))
                {
                    numbers[j] = new Random().nextInt(maxValue);
                }
                while (randomColors[j].equals(randomColors[numRandoms - (i + 1)]))
                {
                    randomColors[j] = colors[new Random().nextInt(colors.length)];
                }
                while (textSizes[j].equals(textSizes[numRandoms - (i + 1)]))
                {
                    textSizes[j] = new Random().nextInt(maxSize - minSize) + minSize;
                }
                while(inRange(margins[j][0], margins[numRandoms - (i + 1)][0]))
                {
                    margins[j][0] = new Random().nextInt(layoutWidth - 40) + 20;
                }
                while(inRange(margins[j][1], margins[numRandoms - (i + 1)][1]))
                {
                    margins[j][1] = new Random().nextInt(layoutHeight - 40) + 20;
                }
            }
        }
        i++;
    }
}

}

我的XML布局中只有一個RelativeLayout，其id為layout

我嘗試使用

((ViewGroup)tv.getParent()).removeView(tv);

之前

layout.addView(tv);

在我的代碼中的各個位置，但沒有一個起作用。

我看着這個和這個 ，但不能找出解決方案。

在哪里以及如何使用removeView（）？

Answer 1

您要一遍又一遍地將相同的TextView添加到布局中。 第一次之后， TextView有一個父級，這就是為什么會出現錯誤的原因。 在循環中初始化TextView ，它將修復您的錯誤：

for(int i = viewCount; i < (viewCount + num); i++)
{
    final TextView tv = new TextView(this);
    tv.setLayoutParams(params[i]);
    tv.setText(String.valueOf(numbers[i]));
    tv.setTextColor(randomColors[i]);
    tv.setTextSize(textSizes[i]);
    createListener(tv);
    layout.addView(tv);
}

如果這樣初始化，則每次都創建一個沒有父級的新TextView 。