为什么我的app力量关闭？

时间：2014-02-20 10:06:53

标签： java android android-layout logcat

我制作待办事项列表应用程序，当我尝试时，强行关闭。我检查了变量，监听器的所有内容，但仍未找到错误。我不知道我在这里错过了什么，至少对我来说，每一个薄的看起来都很完美。

我在这里添加了logcat

java代码：

public class MainActivity extends Activity {

public final static String STOCK_SYMBOL = "com.rashad.mytodolist.MEMO";
private SharedPreferences MemoEntered;
private TableLayout stockScrollView;
private EditText stockSymbolEditText;
Button enterStockSymbolButton;
Button deleteStocksButton;

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

    MemoEntered = getSharedPreferences("stockList", MODE_PRIVATE);

    stockScrollView = (TableLayout) findViewById(R.id.stockScrollView);
    stockSymbolEditText = (EditText) findViewById(R.id.stockSymbolEditText);
    enterStockSymbolButton = (Button) findViewById(R.id.enterStockSymbolButton);
    deleteStocksButton = (Button) findViewById(R.id.deleteStocksButton);

    enterStockSymbolButton.setOnClickListener(enterStockButtonListener);
    deleteStocksButton.setOnClickListener(deleteStocksButtonListener);

    updateSavedStockList(null);
}

private void updateSavedStockList(String newStockSymbol) {
    String[] memo = MemoEntered.getAll().keySet().toArray(new String[0]);
    Arrays.sort(memo, String.CASE_INSENSITIVE_ORDER);

    if (newStockSymbol != null) {
        insertStockInScrollView(newStockSymbol,
                Arrays.binarySearch(memo, newStockSymbol));
    } else {
        for (int i = 0; i < memo.length; ++i) {
            insertStockInScrollView(memo[i], i);
        }
    }
}

private void saveStockSymbol(String newStock) {

    String isTheStockNew = MemoEntered.getString(newStock, null);

    SharedPreferences.Editor preferencesEditor = MemoEntered.edit();
    preferencesEditor.putString(newStock, newStock);
    preferencesEditor.apply();

    if (isTheStockNew == null) {
        updateSavedStockList(newStock);
    }

}

private void insertStockInScrollView(String stock, int arrayIndex) {

    LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View newStockRow = inflater.inflate(R.layout.memorow, null);
    TextView newStockTextView = (TextView) newStockRow
            .findViewById(R.id.stockSymbolTextView);
    newStockTextView.setText(stock);
    stockScrollView.addView(newStockRow, arrayIndex);
}

public OnClickListener enterStockButtonListener = new OnClickListener() {

    @Override
    public void onClick(View arg0) {

        if (stockSymbolEditText.getText().length() > 0) {
            saveStockSymbol(stockSymbolEditText.getText().toString());
            stockSymbolEditText.setText("");

            InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
            imm.hideSoftInputFromWindow(
                    stockSymbolEditText.getWindowToken(), 0);

        } else {
            AlertDialog.Builder builder = new AlertDialog.Builder(
                    MainActivity.this);
            builder.setTitle(R.string.Nothing);
            builder.setPositiveButton(R.string.ok, null);
            builder.setMessage(R.string.Enter_memo);
            AlertDialog theAlertDialog = builder.create();
            theAlertDialog.show();

        }
    }
};

public OnClickListener deleteStocksButtonListener = new OnClickListener() {
    public void onClick(View v) {
        stockScrollView.removeAllViews();
        SharedPreferences.Editor preferencesEditor = MemoEntered.edit();
        preferencesEditor.clear();
        preferencesEditor.apply();
    }

};

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    getMenuInflater().inflate(R.menu.main, menu);

    menu.add(0, 1, 0, "about My ToDo");
    menu.add(0, 2, 1, "Quit");

    return true;

}

public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case 1:

        Intent myIntent = new Intent(MainActivity.this, About.class);
        MainActivity.this.startActivity(myIntent);

        ;
        return true;
    case 2:
        finish();
        return true;
    }
    return false;
}

}

xml文件：

<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/TableLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity"
    android:background="#000000" >

    <TableRow
        android:id="@+id/tableRow1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <EditText
            android:id="@+id/stockSymbolEditText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ems="10" 
            android:inputType="text"
            android:layout_weight="1">

            <requestFocus />
        </EditText>

        <Button
            android:id="@+id/enterStockSymbolButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/Button" />

    </TableRow>

    <TableRow
        android:id="@+id/tableRow2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#006699" >

        <TextView
            android:id="@+id/stockSymbolTextView"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_span="2"
            android:gravity="center_horizontal"
            android:padding="5dp"
            android:text="@string/List"
            android:textColor="#000000"
             />

    </TableRow>

    <TableRow
        android:id="@+id/tableRow3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#006699"
        android:layout_weight="1" >

        <ScrollView
            android:id="@+id/stockScrollView"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_span="2"
            android:padding="5dp" >

            <TableLayout
                android:id="@+id/tablememo"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:padding="5dp" 
                android:stretchColumns="yes" >
            </TableLayout>
        </ScrollView>

    </TableRow>

    <TableRow
        android:id="@+id/tableRow7"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <Button
            android:id="@+id/deleteStocksButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_span="2"
            android:layout_weight="1"
            android:text="@string/Button1" />

    </TableRow>

</TableLayout>

错误的logcat：

    02-20 12:03:47.119: E/AndroidRuntime(2872): FATAL EXCEPTION: main
02-20 12:03:47.119: E/AndroidRuntime(2872): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.rashad.mytodolist/com.rashad.mytodolist.MainActivity}: java.lang.ClassCastException: android.widget.ScrollView
02-20 12:03:47.119: E/AndroidRuntime(2872):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1768)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1784)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at android.app.ActivityThread.access$1500(ActivityThread.java:123)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:939)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at android.os.Looper.loop(Looper.java:130)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at android.app.ActivityThread.main(ActivityThread.java:3835)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at java.lang.reflect.Method.invokeNative(Native Method)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at java.lang.reflect.Method.invoke(Method.java:507)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:864)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:622)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at dalvik.system.NativeStart.main(Native Method)
02-20 12:03:47.119: E/AndroidRuntime(2872): Caused by: java.lang.ClassCastException: android.widget.ScrollView
02-20 12:03:47.119: E/AndroidRuntime(2872):     at com.rashad.mytodolist.MainActivity.onCreate(MainActivity.java:44)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-20 12:03:47.119: E/AndroidRuntime(2872):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722)
02-20 12:03:47.119: E/AndroidRuntime(2872):     ... 11 more

1 个答案:

答案 0 :(得分：2)

<ScrollView
        android:id="@+id/stockScrollView"

... 

stockScrollView = (TableLayout) findViewById(R.id.stockScrollView);

您无法将ScrollView投射到TableLayout。因此，logcat中的java.lang.ClassCastException: android.widget.ScrollView。

要解决此问题，请更改

private TableLayout stockScrollView;

到

private ScrollView stockScrollView;

和

stockScrollView = (TableLayout) findViewById(R.id.stockScrollView);

到

stockScrollView = (ScrollView) findViewById(R.id.stockScrollView);

可能存在其他问题，但这至少是向前迈出的一步。

通常，您需要学习自己调试程序：当出现异常时，从logcat中的堆栈跟踪中查找原因和位置。理论化异常的解释。通过修复理论化问题并再次运行代码来测试您的理论。根据需要重复。

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