Question

我需要你的帮助！！摘自《 Head First Android Development》第二版，例如3：

我有一个名为“ CreatedMessageActivity”的主要活动，目的是将消息传递给名为“ ReceiveMainActivity”的子活动：

以下是“ CreateMessageActivity”的消息：包com.hfad.mymessenger;

        import android.app.Activity;
        import android.content.Intent;
        import android.os.Bundle;
        import android.view.View;
        import android.widget.EditText;

        public class CreateMessageActivity extends Activity {

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

            //Call onSendMessage() when the button is clicked
            public void onSendMessage(View view)
            {
            EditText messageView = (EditText) findViewById(R.id.message);
            String messageText = messageView.getText().toString();
            Intent intent = new Intent(Intent.ACTION_SEND);
            intent.setType("text/plain");
            intent.putExtra(Intent.EXTRA_TEXT, messageText);
            String chooserTitle = "Send message via..";
            Intent chosenIntent = Intent.createChooser(intent,chooserTitle);
            startActivity(chosenIntent);
            }
        }

这是ReceiveMainActivity的代码：

        package com.hfad.mymessenger;

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

        public class ReceiveMainActivity extends Activity {

            public static final String EXTRA_MESSAGE = "message";

            @Override
            protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_receive_message);
            Intent intent = getIntent();
            String messageText = intent.getStringExtra(EXTRA_MESSAGE);
            TextView messageView = (TextView)findViewById(R.id.message);
            messageView.setText(messageText);

            }
        }

AndroidManifest.xml：

        <?xml version="1.0" encoding="utf-8"?>
        <manifest xmlns:android="http://schemas.android.com/apk/res/android"
            package="com.hfad.mymessenger">

            <application
            android:allowBackup="true"
            android:icon="@mipmap/ic_launcher"
            android:label="@string/app_name"
            android:roundIcon="@mipmap/ic_launcher_round"
            android:supportsRtl="true"
            android:theme="@style/AppTheme">
            <activity android:name=".CreateMessageActivity">
                <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

        </manifest>

在应用目录中，这是我的build.gradle文件

        apply plugin: 'com.android.application'

        android {
            compileSdkVersion 27
            defaultConfig {
            applicationId "com.hfad.mymessenger"
            minSdkVersion 19
            targetSdkVersion 27
            versionCode 1
            versionName "1.0"
            testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
            }
            buildTypes {
            release {
                minifyEnabled false
                proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            }
            }
        }

        dependencies {
            implementation fileTree(dir: 'libs', include: ['*.jar'])
            implementation 'com.android.support.constraint:constraint-layout:1.1.3'
            testImplementation 'junit:junit:4.12'
            androidTestImplementation 'com.android.support.test:runner:1.0.2'
            androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
        }

但是由于某种原因，当我调用startActivity（chosenIntent）方法时，在调试它时会收到以下异常：

startNextMatchingActivity只能从顶级活动中调用

任何提示或帮助将不胜感激！

Android意图错误：只能从顶级活动中调用startNextMatchingActivity

0 个答案: