那些遇到过的问题

在类之间传递字符串时,Android应用程序会崩溃

Alp*_*ode 1 java android

我正在尝试在Android中的两个类之间传递一个字符串.第一类是"MainActivity",第二类是"abc".

这是我的MainActivity代码: 

package com.example.passstrings;


import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;

public class MainActivity extends ActionBarActivity {
String pass;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

            pass = "abcabc";
            Intent abc = new Intent(this , abc.class);
            abc.putExtra("key", pass);
            startActivity(abc);






        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment())
                    .commit();
        }
    }


    @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;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            return rootView;
        }
    }

}
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这是我的abc类代码: 

package com.example.passstrings;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

public class abc extends Activity{
TextView tv1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv1=(TextView) findViewById(R.id.textView1);

        Intent intent = getIntent();
        String pass= intent.getExtras().getString("key");
        if(pass!= null){
        tv1.setText(pass);
                }

}

}
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这是我的fragment_main.xml代码: 

<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.passstrings.MainActivity$PlaceholderFragment" >

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView2"
        android:layout_marginLeft="69dp"
        android:layout_marginTop="72dp"
        android:layout_toRightOf="@+id/textView2"
        android:text="TextView" />

</RelativeLayout>
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这是我的LogCat:

04-04 05:34:38.545: I/dalvikvm(734): Could not find method android.content.pm.PackageManager.getActivityLogo, referenced from method android.support.v7.internal.widget.ActionBarView.<init>
04-04 05:34:38.545: W/dalvikvm(734): VFY: unable to resolve virtual method 320: Landroid/content/pm/PackageManager;.getActivityLogo (Landroid/content/ComponentName;)Landroid/graphics/drawable/Drawable;
04-04 05:34:38.545: D/dalvikvm(734): VFY: replacing opcode 0x6e at 0x008b
04-04 05:34:38.545: I/dalvikvm(734): Could not find method android.content.pm.ApplicationInfo.loadLogo, referenced from method android.support.v7.internal.widget.ActionBarView.<init>
04-04 05:34:38.545: W/dalvikvm(734): VFY: unable to resolve virtual method 316: Landroid/content/pm/ApplicationInfo;.loadLogo (Landroid/content/pm/PackageManager;)Landroid/graphics/drawable/Drawable;
04-04 05:34:38.545: D/dalvikvm(734): VFY: replacing opcode 0x6e at 0x0099
04-04 05:34:38.555: D/dalvikvm(734): VFY: dead code 0x008e-0092 in Landroid/support/v7/internal/widget/ActionBarView;.<init> (Landroid/content/Context;Landroid/util/AttributeSet;)V
04-04 05:34:38.555: D/dalvikvm(734): VFY: dead code 0x009c-00a0 in Landroid/support/v7/internal/widget/ActionBarView;.<init> (Landroid/content/Context;Landroid/util/AttributeSet;)V
04-04 05:34:38.675: D/AndroidRuntime(734): Shutting down VM
04-04 05:34:38.675: W/dalvikvm(734): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
04-04 05:34:38.685: E/AndroidRuntime(734): FATAL EXCEPTION: main
04-04 05:34:38.685: E/AndroidRuntime(734): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.passstrings/com.example.passstrings.MainActivity}: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.passstrings/com.example.passstrings.abc}; have you declared this activity in your AndroidManifest.xml?
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.os.Looper.loop(Looper.java:123)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.ActivityThread.main(ActivityThread.java:4627)
04-04 05:34:38.685: E/AndroidRuntime(734):  at java.lang.reflect.Method.invokeNative(Native Method)
04-04 05:34:38.685: E/AndroidRuntime(734):  at java.lang.reflect.Method.invoke(Method.java:521)
04-04 05:34:38.685: E/AndroidRuntime(734):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
04-04 05:34:38.685: E/AndroidRuntime(734):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
04-04 05:34:38.685: E/AndroidRuntime(734):  at dalvik.system.NativeStart.main(Native Method)
04-04 05:34:38.685: E/AndroidRuntime(734): Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.passstrings/com.example.passstrings.abc}; have you declared this activity in your AndroidManifest.xml?
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1404)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.Instrumentation.execStartActivity(Instrumentation.java:1378)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.Activity.startActivityForResult(Activity.java:2817)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:839)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.Activity.startActivity(Activity.java:2923)
04-04 05:34:38.685: E/AndroidRuntime(734):  at com.example.passstrings.MainActivity.onCreate(MainActivity.java:25)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-04 05:34:38.685: E/AndroidRuntime(734):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
04-04 05:34:38.685: E/AndroidRuntime(734):  ... 11 more
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这是我的清单: 

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.passstrings"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.passstrings.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>
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如果我删除"startActivity(abc);" 应用程序不会崩溃,如果使用try&catch应用程序不会崩溃但同时它不执行操作.那可能是什么原因呢？并提前感谢

将活动添加到清单后我的LogCat: 

04-04 05:47:16.555: I/dalvikvm(883): Could not find method android.content.pm.PackageManager.getActivityLogo, referenced from method android.support.v7.internal.widget.ActionBarView.<init>
04-04 05:47:16.555: W/dalvikvm(883): VFY: unable to resolve virtual method 320: Landroid/content/pm/PackageManager;.getActivityLogo (Landroid/content/ComponentName;)Landroid/graphics/drawable/Drawable;
04-04 05:47:16.555: D/dalvikvm(883): VFY: replacing opcode 0x6e at 0x008b
04-04 05:47:16.555: I/dalvikvm(883): Could not find method android.content.pm.ApplicationInfo.loadLogo, referenced from method android.support.v7.internal.widget.ActionBarView.<init>
04-04 05:47:16.565: W/dalvikvm(883): VFY: unable to resolve virtual method 316: Landroid/content/pm/ApplicationInfo;.loadLogo (Landroid/content/pm/PackageManager;)Landroid/graphics/drawable/Drawable;
04-04 05:47:16.565: D/dalvikvm(883): VFY: replacing opcode 0x6e at 0x0099
04-04 05:47:16.565: D/dalvikvm(883): VFY: dead code 0x008e-0092 in Landroid/support/v7/internal/widget/ActionBarView;.<init> (Landroid/content/Context;Landroid/util/AttributeSet;)V
04-04 05:47:16.565: D/dalvikvm(883): VFY: dead code 0x009c-00a0 in Landroid/support/v7/internal/widget/ActionBarView;.<init> (Landroid/content/Context;Landroid/util/AttributeSet;)V
04-04 05:47:16.775: D/AndroidRuntime(883): Shutting down VM
04-04 05:47:16.775: W/dalvikvm(883): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
04-04 05:47:16.786: E/AndroidRuntime(883): FATAL EXCEPTION: main
04-04 05:47:16.786: E/AndroidRuntime(883): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.passstrings/com.example.passstrings.abc}: java.lang.NullPointerException
04-04 05:47:16.786: E/AndroidRuntime(883):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
04-04 05:47:16.786: E/AndroidRuntime(883):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
04-04 05:47:16.786: E/AndroidRuntime(883):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
04-04 05:47:16.786: E/AndroidRuntime(883):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
04-04 05:47:16.786: E/AndroidRuntime(883):  at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 05:47:16.786: E/AndroidRuntime(883):  at android.os.Looper.loop(Looper.java:123)
04-04 05:47:16.786: E/AndroidRuntime(883):  at android.app.ActivityThread.main(ActivityThread.java:4627)
04-04 05:47:16.786: E/AndroidRuntime(883):  at java.lang.reflect.Method.invokeNative(Native Method)
04-04 05:47:16.786: E/AndroidRuntime(883):  at java.lang.reflect.Method.invoke(Method.java:521)
04-04 05:47:16.786: E/AndroidRuntime(883):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
04-04 05:47:16.786: E/AndroidRuntime(883):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
04-04 05:47:16.786: E/AndroidRuntime(883):  at dalvik.system.NativeStart.main(Native Method)
04-04 05:47:16.786: E/AndroidRuntime(883): Caused by: java.lang.NullPointerException
04-04 05:47:16.786: E/AndroidRuntime(883):  at com.example.passstrings.abc.onCreate(abc.java:20)
04-04 05:47:16.786: E/AndroidRuntime(883):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-04 05:47:16.786: E/AndroidRuntime(883):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
04-04 05:47:16.786: E/AndroidRuntime(883):  ... 11 more
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和更新后我的清单:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.passstrings"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.passstrings.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
       <activity android:name="com.example.passstrings.abc" />
    </application>

</manifest>
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ale*_*lex 5

您需要将第二个添加Activity到Androidmanifest.xml文件中.

<activity android:name="com.example.passstrings.abc" />
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  • 我看不到更新,你有没有做到？检查你的`logcat`以查看错误是否发生了变化. (2认同)

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