Question

当我运行我的应用程序时，它会立即崩溃。我使用Android监视器，看起来当应用程序启动它时使用的内存多于分配的内存（下面有一个屏幕截图显示了这一点）。我只为计算机开发，所以我不担心内存，但似乎即使是两个中等大小的阵列也超过了极限。

public class MainActivity extends AppCompatActivity {

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

    //input initialization
    final EditText numberInput = (EditText) findViewById(R.id.number_input);
    Button submit = (Button) findViewById(R.id.submit_button);
    Button zero = (Button) findViewById((R.id.resetButton));

    //progress bar initialization
    final ProgressBar progressBars[] = null;
    progressBars[0] = (ProgressBar)findViewById(R.id.progressBar0);
    progressBars[1] = (ProgressBar)findViewById(R.id.progressBar1);
    progressBars[2] = (ProgressBar)findViewById(R.id.progressBar2);
    progressBars[3] = (ProgressBar)findViewById(R.id.progressBar3);
    progressBars[4] = (ProgressBar)findViewById(R.id.progressBar4);
    progressBars[5] = (ProgressBar)findViewById(R.id.progressBar5);
    progressBars[6] = (ProgressBar)findViewById(R.id.progressBar6);
    progressBars[7] = (ProgressBar)findViewById(R.id.progressBar7);
    progressBars[8] = (ProgressBar)findViewById(R.id.progressBar8);
    progressBars[9] = (ProgressBar)findViewById(R.id.progressBar9);
    progressBars[10] = (ProgressBar)findViewById(R.id.progressBar10);
    progressBars[11] = (ProgressBar)findViewById(R.id.progressBar11);
    progressBars[12] = (ProgressBar)findViewById(R.id.progressBar12);
    progressBars[13] = (ProgressBar)findViewById(R.id.progressBar13);
    progressBars[14] = (ProgressBar)findViewById(R.id.progressBar14);
    progressBars[15] = (ProgressBar)findViewById(R.id.progressBar15);
    progressBars[16] = (ProgressBar)findViewById(R.id.progressBar16);
    progressBars[17] = (ProgressBar)findViewById(R.id.progressBar17);

    //variable value initialization
    final TextView textViews[] = null;
    textViews[0] = (TextView)findViewById(R.id.value0);
    textViews[1] = (TextView)findViewById(R.id.value1);
    textViews[2] = (TextView)findViewById(R.id.value2);
    textViews[3] = (TextView)findViewById(R.id.value3);
    textViews[4] = (TextView)findViewById(R.id.value4);
    textViews[5] = (TextView)findViewById(R.id.value5);
    textViews[6] = (TextView)findViewById(R.id.value6);
    textViews[7] = (TextView)findViewById(R.id.value7);
    textViews[8] = (TextView)findViewById(R.id.value8);
    textViews[9] = (TextView)findViewById(R.id.value9);
    textViews[10] = (TextView)findViewById(R.id.value10);
    textViews[11] = (TextView)findViewById(R.id.value11);
    textViews[12] = (TextView)findViewById(R.id.value12);
    textViews[13] = (TextView)findViewById(R.id.value13);
    textViews[14] = (TextView)findViewById(R.id.value14);
    textViews[15] = (TextView)findViewById(R.id.value15);
    textViews[16] = (TextView)findViewById(R.id.value16);
    textViews[17] = (TextView)findViewById(R.id.value17);

    submit.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            //get string from input and convert it into an integer
            int numberInt = Integer.parseInt(numberInput.getText().toString());
            //set the values of the progress bars
            for(int i = 0; i < progressBars.length; i++)
            {
                progressBars[i].setProgress(numberInt);
            }
            //set the value of the variable display
            for (int i = 0; i < textViews.length; i++)
            {
                textViews[i].setText(numberInt);
            }
        }
    });

    zero.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            //reset the progress bars to 0
            for(int i = 0; i < progressBars.length; i++)
            {
                progressBars[i].setProgress(0);
            }


            //reset the variable display to "~~~"
            for (int i = 0; i < textViews.length; i++)
            {
                textViews[i].setText("~~~");
            }
        }
    });
}

我已经尝试过帮助＆gt;编辑自定义VM选项...而不是修复问题导致Android Studio拒绝打开。我是Java的新手，所以我错过了内存泄漏，是否有更有效的方法将项目存储在两个数组中，或者我只是需要增加应用程序的内存？

Answer 1

您需要了解有关基本Java结构的更多信息。

您没有为阵列分配任何内存。 Java与JavaScript不同 - 它不会为您分配的数组元素自动分配空间。

final ProgressBar progressBars[] = null;
progressBars[0] = (ProgressBar)findViewById(R.id.progressBar0);

此代码段将失败，因为该数组为null（它没有为任何元素分配空间）。当您尝试为其分配元素时，它将抛出NullPointerException。您必须在创建阵列时分配空间：

final ProgressBar progressBars[] = new ProgressBar[18];
progressBars[0] = (ProgressBar)findViewById(R.id.progressBar0);

我的建议是先完成一些Java教程。还应注意有关查看Logcat的评论 - 当您的应用程序崩溃时，它（通常！）会告诉您崩溃发生在源中的确切位置以及原因。

内存问题Android应用程序

1 个答案: