java - 致命异常无法启动 Activity ComponentInfo

Question

以下 Android Studio 1.5 MainActivity.java 代码会在标题中生成错误，并带有 You need to use a Theme.AppCompat theme

public class MainActivity extends AppCompatActivity {

    private WebView mWebView;

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

        mWebView = (WebView) findViewById(R.id.activity_main_webview);
        WebSettings webSettings = mWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        mWebView.loadUrl("https://staging.site.me/");
        mWebView.setWebViewClient(new me.site.siteand.MyAppWebViewClient(){
            @Override
            public void onPageFinished(WebView view, String url) {
                //hide loading image
                findViewById(R.id.progressBar1).setVisibility(View.GONE);
                //show webview
                findViewById(R.id.activity_main_webview).setVisibility(View.VISIBLE);
            }});


    }

    @Override
    public void onBackPressed() {
        if(mWebView.canGoBack()) {
            mWebView.goBack();
        } else {
            super.onBackPressed();
        }
    }


    private ShareActionProvider mShareActionProvider;
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        /** Inflating the current activity's menu with res/menu/items.xml */
        getMenuInflater().inflate(R.menu.menu_main, menu);

        /** Getting the actionprovider associated with the menu item whose id is share */
        mShareActionProvider = (ShareActionProvider) menu.findItem(R.id.share).getActionProvider();

        /** Setting a share intent */
        mShareActionProvider.setShareIntent(getDefaultShareIntent());

        return super.onCreateOptionsMenu(menu);

    }

    /** Returns a share intent */
    private Intent getDefaultShareIntent(){
        Intent intent = new Intent(Intent.ACTION_SEND);
        intent.setType("text/plain");
        intent.putExtra(Intent.EXTRA_SUBJECT, "Convert Website to Android Application");
        intent.putExtra(Intent.EXTRA_TEXT," Vist www.AndroidWebViewApp.com if you Want to Convert your Website or Blog to Android Application");
        return intent;
    }


}

styles.xml 包括

<style name="AppTheme" parent="Theme.AppCompat">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>

并且activity_main.xml有其初始化 block

<android.support.design.widget.CoordinatorLayout ...>
</android.support.design.widget.CoordinatorLayout>

编辑 list 文件现在状态

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

    <uses-permission android:name="android.permission.INTERNET" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

        <activity
            android:name=".Splash"
            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>

按照下面的建议；解决了问题。

Answer 1

检查您的 AndroidManisfest.xml。你应该有这样的东西:

<activity
    android:name=".MainActivity"
    android:label="@string/app_name"
    android:theme="@style/AppTheme">
    <intent-filter>
        <action android:name="android.intent.action.MAIN"/>

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

这里重要的部分是android:theme="@style/AppTheme"。您的 list 很可能错过了它。