Question

我想创建一个应用程序，但是当我运行时，logcat显示：FATAL EXCEPTION MAIN

CODE：

package com.example.mythirdapp;

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Color;
import android.graphics.Typeface;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;

public class MainActivity extends Activity {
       SQLiteDatabase pf;

       TableRow tablerow;
       TextView t,t1,t2,t3,t4,t5;    
       String first_name,last_name;
       String userGender; 


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        pf=openOrCreateDatabase("Profile",MODE_PRIVATE,null);
        pf.execSQL("CREATE TABLE IF NOT EXISTS Persone(first_name VARCHAR,last_name VARCHAR,userGender VARCHAR);");
    }


    public void add(View view){
        EditText fn  = (EditText)findViewById(R.id.first_name);
        EditText ln   = (EditText)findViewById(R.id.last_name);

        first_name=fn.getText().toString();
        last_name =ln.getText().toString();

        boolean checked = ((RadioButton) view).isChecked();

        // Check which radio button was clicked
        switch(view.getId()) {
            case R.id.radio_female:
                if (checked)
                    userGender = "female";
                break;
            case R.id.radio_male:
                if (checked)
                   userGender = "male";
                break;
        }

        pf.execSQL("INSERT INTO Persone VALUES('"+first_name+"','"+last_name+"','"+userGender+"');");
    }



    public void show(View view){
        Cursor c = pf.rawQuery("SELECT * FROM Persone", null);
        int count = c.getCount();
        c.moveToFirst();
        TableLayout tablelayout = new TableLayout(getApplicationContext());
        tablelayout.setVerticalScrollBarEnabled(true);
        TableRow tablerow;
        TextView t,t1,t2,t3,t4,t5;
        tablerow = new TableRow(getApplicationContext());

        t = new TextView(getApplicationContext());
        t.setText("First Name");
        t.setTextColor(Color.RED);
        t.setTypeface(null,Typeface.BOLD);
        t.setPadding(20,20,20,20);
        tablerow.addView(t);

        t3 = new TextView(getApplicationContext());
        t3.setText("Last Name");
        t3.setTextColor(Color.RED);
        t3.setTypeface(null,Typeface.BOLD);
        t3.setPadding(20,20,20,20);
        tablerow.addView(t3);

        t4 = new TextView(getApplicationContext());
        t4.setText("Gender");
        t4.setTextColor(Color.RED);
        t4.setTypeface(null,Typeface.BOLD);
        t4.setPadding(20,20,20,20);
        tablerow.addView(t4);

        tablelayout.addView(tablerow);
        for(Integer j = 0;j<count;j++)
        {
          tablerow = new TableRow(getApplicationContext());

          t1 = new TextView(getApplicationContext());
          t1.setText(c.getString(c.getColumnIndex("first_name")));
          t1.setPadding(20, 20, 20, 20);


          t2 = new TextView(getApplicationContext());
          t2.setText(c.getString(c.getColumnIndex("last_name")));
          t2.setPadding(20, 20, 20, 20);

          t5 = new TextView(getApplicationContext());
          t5.setText(c.getString(c.getColumnIndex("userGender")));
          t5.setPadding(20, 20, 20, 20);



          tablerow.addView(t1);
          tablerow.addView(t2);
          tablerow.addView(t5);


          tablelayout.addView(tablerow);

          c.moveToNext();
        }
        setContentView(tablelayout);
        pf.close();
    }
}

＆＃13;

<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="com.example.mythirdapp.MainActivity" >

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="14dp"
        android:text="@string/last_name"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <EditText
        android:id="@+id/first_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/textView1"
        android:layout_alignBottom="@+id/textView1"
        android:layout_alignParentRight="true"
        android:layout_toRightOf="@+id/textView1"
        android:ems="10"
        android:inputType="textPersonName" >

        <requestFocus android:layout_width="match_parent" />

    </EditText>

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="14dp"
        android:text="@string/first_name"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_marginBottom="16dp"
        android:onClick="add"
        android:text="@string/add" />

    <Button
        android:id="@+id/Button01"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button1"
        android:layout_alignBottom="@+id/button1"
        android:layout_alignRight="@+id/last_name"
        android:onClick="show"
        android:text="@string/show" />

    <EditText
        android:id="@+id/last_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/first_name"
        android:layout_below="@+id/textView1"
        android:ems="10"
        android:inputType="textPersonName" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView2"
        android:layout_below="@+id/last_name"
        android:layout_marginTop="14dp"
        android:text="@string/gender"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <RadioGroup
        android:id="@+id/radio_gender"
        android:layout_width="wrap_content"
        android:layout_height="fill_parent"
        android:layout_alignRight="@+id/Button01"
        android:layout_alignTop="@+id/textView3"
        android:layout_toRightOf="@+id/button1"
        >

        <RadioButton
            android:id="@+id/radio_female"
            android:text="@string/radio_female"
            android:onClick="add" />

        <RadioButton
            android:id="@+id/radio_male"
            android:text="@string/radio_male" 
            android:onClick="add"/>

    </RadioGroup>

</RelativeLayout>

＆＃13;

比logcat

10-02 10:25:55.156: E/AndroidRuntime(854): FATAL EXCEPTION: main
10-02 10:25:55.156: E/AndroidRuntime(854): Process: com.example.mythirdapp, PID: 854
10-02 10:25:55.156: E/AndroidRuntime(854): java.lang.IllegalStateException: Could not execute method of the activity
10-02 10:25:55.156: E/AndroidRuntime(854):  at android.view.View$1.onClick(View.java:3823)
10-02 10:25:55.156: E/AndroidRuntime(854):  at android.view.View.performClick(View.java:4438)
10-02 10:25:55.156: E/AndroidRuntime(854):  at android.view.View$PerformClick.run(View.java:18422)
10-02 10:25:55.156: E/AndroidRuntime(854):  at android.os.Handler.handleCallback(Handler.java:733)
10-02 10:25:55.156: E/AndroidRuntime(854):  at android.os.Handler.dispatchMessage(Handler.java:95)
10-02 10:25:55.156: E/AndroidRuntime(854):  at android.os.Looper.loop(Looper.java:136)
10-02 10:25:55.156: E/AndroidRuntime(854):  at android.app.ActivityThread.main(ActivityThread.java:5017)
10-02 10:25:55.156: E/AndroidRuntime(854):  at java.lang.reflect.Method.invokeNative(Native Method)
10-02 10:25:55.156: E/AndroidRuntime(854):  at java.lang.reflect.Method.invoke(Method.java:515)
10-02 10:25:55.156: E/AndroidRuntime(854):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
10-02 10:25:55.156: E/AndroidRuntime(854):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
10-02 10:25:55.156: E/AndroidRuntime(854):  at dalvik.system.NativeStart.main(Native Method)
10-02 10:25:55.156: E/AndroidRuntime(854): Caused by: java.lang.reflect.InvocationTargetException
10-02 10:25:55.156: E/AndroidRuntime(854):  at java.lang.reflect.Method.invokeNative(Native Method)
10-02 10:25:55.156: E/AndroidRuntime(854):  at java.lang.reflect.Method.invoke(Method.java:515)
10-02 10:25:55.156: E/AndroidRuntime(854):  at android.view.View$1.onClick(View.java:3818)
10-02 10:25:55.156: E/AndroidRuntime(854):  ... 11 more
10-02 10:25:55.156: E/AndroidRuntime(854): Caused by: java.lang.ClassCastException: android.widget.Button cannot be cast to android.widget.RadioButton
10-02 10:25:55.156: E/AndroidRuntime(854):  at com.example.mythirdapp.MainActivity.add(MainActivity.java:46)
10-02 10:25:55.156: E/AndroidRuntime(854):  ... 14 more

我认为这是settext问题，但我不知道为什么。我想在sql中添加文本。但是当谈到增加性别时，它就出错了

Answer 1

你的问题在这里

<Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_marginBottom="16dp"
        android:onClick="add"
        android:text="@string/add" />

正好在这里android:onClick="add" 在add(View view)方法中，您将View视图投射到RadioButton，

boolean checked = ((RadioButton) view).isChecked();

有时它会是Button，因为你已经将onClick声明为“添加”按钮

这就是你有这个例外的原因

ClassCastException: android.widget.Button cannot be cast to android.widget.RadioButton

所以你要么通过检查视图的实例来解决这个问题，要么为Button

声明另一个方法

Answer 2

您的代码运行正常。我不知道你如何实现你的布局，但假设它是最简单的：有两个editTexts，两个radioButtons和一个按钮来显示结果。这就是我实现这些事情的方式。

<强> MainActivity.class

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Color;
import android.graphics.Typeface;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;

public class MainActivity extends Activity
{
    SQLiteDatabase pf;

TableRow tablerow;
TextView t, t1, t2, t3, t4, t5;
String first_name, last_name;
String userGender;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    pf = openOrCreateDatabase("Profile", MODE_PRIVATE, null);
    pf.execSQL("CREATE TABLE IF NOT EXISTS Persone(first_name VARCHAR,last_name VARCHAR,userGender VARCHAR);");
}

public void add(View view)
{
    EditText fn = (EditText) findViewById(R.id.first_name);
    EditText ln = (EditText) findViewById(R.id.last_name);

    first_name = fn.getText().toString();
    last_name = ln.getText().toString();

    boolean checked = ((RadioButton) view).isChecked();

    // Check which radio button was clicked
    switch (view.getId())
    {
        case R.id.radio_female:
            if (checked)
                userGender = "female";
            break;
        case R.id.radio_male:
            if (checked)
                userGender = "male";
            break;
    }

    pf.execSQL("INSERT INTO Persone VALUES('" + first_name + "','" + last_name + "','" + userGender + "');");
}

public void show(View view)
{
    Cursor c = pf.rawQuery("SELECT * FROM Persone", null);
    int count = c.getCount();
    c.moveToFirst();
    TableLayout tablelayout = new TableLayout(getApplicationContext());
    tablelayout.setVerticalScrollBarEnabled(true);
    TableRow tablerow;
    TextView t, t1, t2, t3, t4, t5;
    tablerow = new TableRow(getApplicationContext());

    t = new TextView(getApplicationContext());
    t.setText("First Name");
    t.setTextColor(Color.RED);
    t.setTypeface(null, Typeface.BOLD);
    t.setPadding(20, 20, 20, 20);
    tablerow.addView(t);

    t3 = new TextView(getApplicationContext());
    t3.setText("Last Name");
    t3.setTextColor(Color.RED);
    t3.setTypeface(null, Typeface.BOLD);
    t3.setPadding(20, 20, 20, 20);
    tablerow.addView(t3);

    t4 = new TextView(getApplicationContext());
    t4.setText("Gender");
    t4.setTextColor(Color.RED);
    t4.setTypeface(null, Typeface.BOLD);
    t4.setPadding(20, 20, 20, 20);
    tablerow.addView(t4);

    tablelayout.addView(tablerow);
    for (Integer j = 0; j < count; j++)
    {
        tablerow = new TableRow(getApplicationContext());

        t1 = new TextView(getApplicationContext());
        t1.setText(c.getString(c.getColumnIndex("first_name")));
        t1.setPadding(20, 20, 20, 20);

        t2 = new TextView(getApplicationContext());
        t2.setText(c.getString(c.getColumnIndex("last_name")));
        t2.setPadding(20, 20, 20, 20);

        t5 = new TextView(getApplicationContext());
        t5.setText(c.getString(c.getColumnIndex("userGender")));
        t5.setPadding(20, 20, 20, 20);

        tablerow.addView(t1);
        tablerow.addView(t2);
        tablerow.addView(t5);

        tablelayout.addView(tablerow);

        c.moveToNext();
    }
    setContentView(tablelayout);
    pf.close();
}
}

<强> activity_main.xml中

<LinearLayout 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:orientation="vertical"
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="com.example.stackoverflow_1.MainActivity" >

<EditText
    android:id="@+id/first_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

<EditText
    android:id="@+id/last_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:ems="10" />

<RadioButton
    android:id="@+id/radio_female"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="add"
    android:text="Female" />

<RadioButton
    android:id="@+id/radio_male"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="add"
    android:text="Male" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="show"
    android:text="Show" />

</LinearLayout>

致命异常主要是sql数据库

2 个答案: