第二个 .xml 文件未在 android 上打开

【问题标题】：Second .xml file not opening on android第二个 .xml 文件未在 android 上打开
【发布时间】：2014-01-04 15:30:17
【问题描述】：

我正在做 android 应用程序来将摄氏度的值更改为华氏度，反之亦然。但是当打开第二个 xml 页面时，它停止工作。

activity_main.xml：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
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" >

<TextView
    android:id="@+id/textViewHello"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />

<Button
    android:id="@+id/buttonGO"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_marginBottom="147dp"
    android:layout_toRightOf="@+id/textViewHello"
    android:text="@string/button1_str" />

<EditText
    android:id="@+id/editTextFarh"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_below="@+id/textViewHello"
    android:layout_marginRight="21dp"
    android:layout_marginTop="34dp"
    android:ems="10"
    android:inputType="numberDecimal"
    android:text="@string/FarhTextStr" >

    <requestFocus />
</EditText>

<EditText
    android:id="@+id/editTextCelc"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/editTextFarh"
    android:layout_below="@+id/editTextFarh"
    android:layout_marginTop="27dp"
    android:ems="10"
    android:inputType="numberDecimal"
    android:text="@string/CelcTextStr" />

</RelativeLayout>

new_page.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<Button
    android:id="@+id/buttonBACK"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:layout_marginLeft="87dp"
    android:layout_marginTop="67dp"
    android:text="@string/button2_str" />

<TextView
    android:id="@+id/textViewHello"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:layout_marginLeft="33dp"
    android:layout_marginTop="15dp"
    android:text="@string/hello" />

<Button
    android:id="@+id/buttonChangeText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/buttonBACK"
    android:layout_alignRight="@+id/buttonBACK"
    android:layout_below="@+id/buttonBACK"
    android:layout_marginTop="24dp"
    android:text="@string/hello_world" />

<EditText
    android:id="@+id/editTextCelc2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_below="@+id/buttonChangeText"
    android:layout_marginRight="22dp"
    android:layout_marginTop="53dp"
    android:ems="10"
    android:inputType="numberDecimal"
    android:text="@string/CelcTextStr" >

    <requestFocus />
</EditText>

<EditText
    android:id="@+id/editTextFarh2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/buttonChangeText"
    android:layout_below="@+id/editTextCelc2"
    android:layout_marginTop="44dp"
    android:ems="10"
    android:inputType="numberDecimal"
    android:text="@string/FarhTextStr" />

</RelativeLayout>

MainActivity.java：

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {

Button btGo;

private static final String FAHR_VALUE = "FAHR_VALUE";
private static final String CELC_VALUE = "CELC_VALUE";

EditText FahrET;
EditText CelcET;

private double fahrValue;
private double celcValue;

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

    if(savedInstanceState == null){
        fahrValue = 0.0;
        celcValue = 0.0;
    }
    else{
        fahrValue = savedInstanceState.getDouble(FAHR_VALUE);
        celcValue = savedInstanceState.getDouble(CELC_VALUE);
    }

    FahrET = (EditText) findViewById(R.id.editTextFarh);
    CelcET = (EditText) findViewById(R.id.editTextCelc);

    FahrET.addTextChangedListener(changeValueListener);

    updateFinalValue();

    btGo = (Button) findViewById(R.id.buttonGO);
    btGo.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Intent i = new Intent(MainActivity.this, NewPage.class);
            startActivity(i);
        }
    });
}

private TextWatcher changeValueListener = new TextWatcher(){

    @Override
    public void afterTextChanged(Editable s) {
        // TODO Auto-generated method stub

    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count,
            int after) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before,
            int count) {
        // TODO Auto-generated method stub
        try{
            fahrValue = Double.parseDouble(s.toString());
        }
        catch (NumberFormatException e){
            fahrValue = 0.0;
        }

        updateFinalValue();

    }

};

private void updateFinalValue(){

    double finalResult = (((fahrValue - 32) * 5) / 9);

    CelcET.setText(String.format("%.02f", finalResult));
}

protected void onSaveInstanceState(Bundle outState){

    super.onSaveInstanceState(outState);

    outState.putDouble(FAHR_VALUE, fahrValue);
    outState.putDouble(CELC_VALUE, celcValue);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

NewPage.java：

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class NewPage extends Activity {

TextView Hello;

private static final String FAHR_VALUE2 = "FAHR_VALUE2";
private static final String CELC_VALUE2 = "CELC_VALUE2";

private double celcValue2;
private double fahrValue2;

EditText newCelcET;
EditText newFahrET;


Button btBack;
Button chText;

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

    if(savedInstanceState == null){
        celcValue2 = 0.0;
        fahrValue2 = 0.0;

    }
    else{
        celcValue2 = savedInstanceState.getDouble(CELC_VALUE2);
        fahrValue2 = savedInstanceState.getDouble(FAHR_VALUE2);
    }

    newCelcET = (EditText) findViewById(R.id.editTextCelc2);
    newFahrET = (EditText) findViewById(R.id.editTextFarh2);

    newFahrET.addTextChangedListener(changeValueListenerTwo);



    Hello = (TextView) findViewById(R.id.textViewHello);

    btBack = (Button) findViewById(R.id.buttonBACK);
    btBack.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            setResult(RESULT_OK);
            finish();
        }
    });
    chText = (Button) findViewById(R.id.buttonChangeText);
    chText.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Hello.setText("It Worked!!!");
        }
    });

    FinalValue2();

}

private TextWatcher changeValueListenerTwo = new TextWatcher() {

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count)    

    {   // TODO Auto-generated method stub


    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count,
            int after) {
        // TODO Auto-generated method stub

    }

    @Override
    public void afterTextChanged(Editable s) {
        // TODO Auto-generated method stub
        try{
            fahrValue2 = Double.parseDouble(s.toString());
        }
        catch (NumberFormatException e){
            fahrValue2 = 0.0;
        }

        FinalValue2();
    }
};

private void FinalValue2(){
    double finalResult2 = (((celcValue2 * 9) / 5) + 32);

    newFahrET.setText(String.format("%.02f", finalResult2));
}


protected void onSaveInstanceState(Bundle outState){

    super.onSaveInstanceState(outState);

    outState.putDouble(FAHR_VALUE2, fahrValue2);
    outState.putDouble(CELC_VALUE2, celcValue2);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

我做了一些测试，发现在我使用FinalValue2函数时出现了错误。

这是错误：

01-04 15:11:34.323: E/AndroidRuntime(2051): FATAL EXCEPTION: main

01-04 15:11:34.323: E/AndroidRuntime(2051): java.lang.StackOverflowError

01-04 15:11:34.323: E/AndroidRuntime(2051):     at java.lang.StringBuilder.append(StringBuilder.java:125)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at java.util.Formatter.transform_f(Formatter.java:2245)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at java.util.Formatter.transformFromFloat(Formatter.java:2097)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at java.util.Formatter.transform(Formatter.java:1496)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at java.util.Formatter.doFormat(Formatter.java:1101)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at java.util.Formatter.format(Formatter.java:1062)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at java.util.Formatter.format(Formatter.java:1031)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at java.lang.String.format(String.java:2177)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at java.lang.String.format(String.java:2151)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.FinalValue2(NewPage.java:110)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.access$1(NewPage.java:107)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage$1.afterTextChanged(NewPage.java:103
)
01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.sendAfterTextChanged(TextView.java:6330)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2737)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2598)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.EditText.setText(EditText.java:78)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2573)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.FinalValue2(NewPage.java:110)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.access$1(NewPage.java:107)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage$1.afterTextChanged(NewPage.java:103)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.sendAfterTextChanged(TextView.java:6330)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2737)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2598)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.EditText.setText(EditText.java:78)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2573)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.FinalValue2(NewPage.java:110)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.access$1(NewPage.java:107)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage$1.afterTextChanged(NewPage.java:103)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.sendAfterTextChanged(TextView.java:6330)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2737)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2598)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.EditText.setText(EditText.java:78)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2573)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.FinalValue2(NewPage.java:110)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.access$1(NewPage.java:107)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage$1.afterTextChanged(NewPage.java:103)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.sendAfterTextChanged(TextView.java:6330)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2737)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2598)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.EditText.setText(EditText.java:78)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2573)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.FinalValue2(NewPage.java:110)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.access$1(NewPage.java:107)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage$1.afterTextChanged(NewPage.java:103)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.sendAfterTextChanged(TextView.java:6330)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2737)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2598)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.EditText.setText(EditText.java:78)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2573)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.FinalValue2(NewPage.java:110)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.access$1(NewPage.java:107)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage$1.afterTextChanged(NewPage.java:103)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.sendAfterTextChanged(TextView.java:6330)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2737)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2598)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.EditText.setText(EditText.java:78)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2573)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.FinalValue2(NewPage.java:110)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.access$1(NewPage.java:107)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage$1.afterTextChanged(NewPage.java:103)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.sendAfterTextChanged(TextView.java:6330)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2737)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2598)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.EditText.setText(EditText.java:78)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at android.widget.TextView.setText(TextView.java:2573)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.NewPage.FinalValue2(NewPage.java:110)

01-04 15:11:34.323: E/AndroidRuntime(2051):     at com.luisoms.doubletest.N

我已经做了很多尝试来修复 TextWatcher，但似乎不是问题，但我就是找不到它

【问题讨论】：

  • 你能发布错误信息吗？
  • 你应该用小写字母命名你的方法。这是标准的 Java 约定。
  • 我已经试过了，还是不行

标签： java android xml android-layout


【解决方案1】：

您的TextWatcher 更改它正在监视的文本，触发对观察者的另一个调用，更改它正在监视的文本，触发对观察者的另一个调用，......等等，直到没有更多的堆栈可以进一步调用方法。

修复它的一种方法是在类中设置一个布尔标志，以便您可以区分用户发起的编辑和代码发起的编辑：

boolean mIsInTextWatcher = false;

@Override
public void afterTextChanged(Editable s) {
    if (mIsInTextWatcher)
        return;
    mIsInTextWatcher = true;

    // do whatever you do, possibly modifying the text

    mIsInTextWatcher = false;
}

【讨论】：

  • 我对此很陌生，所以我不太明白它是如何工作的
  • 你没有任何与 TextWatcher 无关的想法吗？
  • 堆栈跟踪是这么说的。
  • 但我完全按照你说的做了，但没有奏效。我只需要把它放在第二个 .java 上吗？
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