Question

所以我决定为我的网站制作一个Android应用程序（没有多少人阅读它，但我认为它在我的Ucas上看起来不错！我的问题是，在我的手机上显示启动画面后应用程序崩溃，我对Android应用程序开发很新，所以我不确定我做错了什么。

我已将我的源代码上传到Github，以便您可以更好地查看它！

这是我的一些代码：

MainActivity.java

package com.alffiw.alffisblog;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ProgressBar;


public class MainActivity extends Activity {

    private WebView mWebView;
    ProgressBar progressBar;


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

        mWebView = (WebView) findViewById(R.id.activity_main_webview);

        progressBar = (ProgressBar) findViewById(R.id.progressBar1);

        WebSettings webSettings = mWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        mWebView.loadUrl("http://www.coderefer.com");
        mWebView.setWebViewClient(new HelloWebViewClient());


    }

    private class HelloWebViewClient extends WebViewClient{


        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            // TODO Auto-generated method stub
            super.onPageStarted(view, url, favicon);
        }

        @Override
        public boolean shouldOverrideUrlLoading(WebView webView, String url)
        {
            webView.loadUrl(url);
            return true;
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            // TODO Auto-generated method stub
            super.onPageFinished(view, url);

            progressBar.setVisibility(view.GONE);
        }

    }


    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event)
    { //if back key is pressed
        if((keyCode == KeyEvent.KEYCODE_BACK)&& mWebView.canGoBack())
        {
            mWebView.goBack();
            return true;

        }

        return super.onKeyDown(keyCode, event);

    }




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

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    public void onBackPressed() {
        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
                MainActivity.this);

        // set title
        alertDialogBuilder.setTitle("Exit");

        // set dialog message
        alertDialogBuilder
                .setMessage("Do you really want to exit?")
                .setCancelable(false)
                .setPositiveButton("Yes",new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog,int id) {
                        // if this button is clicked, close
                        // current activity
                        MainActivity.this.finish();
                    }
                })
                .setNegativeButton("No",new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog,int id) {
                        // if this button is clicked, just close
                        // the dialog box and do nothing
                        dialog.cancel();
                    }
                });

        // create alert dialog
        AlertDialog alertDialog = alertDialogBuilder.create();

        // show it
        alertDialog.show();
    }
}

SplashScreen.java

package com.alffiw.alffisblog;

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

public class SplashScreen extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.splash);

        Thread timerThread = new Thread(){
            public void run(){
                try{
                    sleep(3000);
                }catch(InterruptedException e){
                    e.printStackTrace();
                }finally{
                    Intent intent = new Intent(SplashScreen.this,MainActivity.class);
                    startActivity(intent);
                }
            }
        };
        timerThread.start();
    }

    @Override
    protected void onPause() {
        // TODO Auto-generated method stub
        super.onPause();
        finish();
    }

}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
    <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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <ProgressBar
        android:layout_centerHorizontal="true"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:layout_gravity="center_vertical|center_horizontal"
        android:id="@+id/progressBar1"/>

    <TextView
        android:layout_below="@+id/progressBar1"
        android:layout_height="wrap_content"
        android:id="@+id/LoadingText"
        android:layout_width="fill_parent"
        android:text="Loading, Please Wait.."
        android:textSize="20sp"
        android:gravity="center_horizontal">
    </TextView>

    <WebView
        android:id="@+id/activity_main_webview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    </RelativeLayout>

content_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.alffiw.alffisblog.MainActivity"
    tools:showIn="@layout/activity_main">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />
</RelativeLayout>

splash.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/splash_image"
    android:orientation="vertical">

</LinearLayout>

的AndroidManifest.xml

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.alffiw.alffisblog">
    <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=".SplashScreen"
            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=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="com.coderefer.androidsplashscreenexample.MAINACTIVITY" />

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

</manifest>

提前感谢您的帮助！

Answer 1

而不是使用线程调用Handler

protected void onCreate(Bundle savedInstanceState) {

    //your stuff.....
    new android.os.Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
            if (!isFinishing()) {//just to make sure user didn,t press back button
                Intent mainIntent = new Intent(Splashscreen.this, MainActivity.class);
                startActivity(mainIntent);
                finish();
            }
        }
    }, 3000);//waiting time

}

Answer 2

您无法在您创建的主题中调用startActivity(intent)表单。首先，因为startActivity(...)是Context方法，其次，您需要在UI线程上执行此语句。

试试这个：

@Override
protected void onCreate(Bundle savedInstanceState) {

    ...

    final Context activity = this;
    Thread timerThread = new Thread(new Runnable(
            public void run(){
                try{
                    sleep(3000);
                }catch(InterruptedException e){
                    e.printStackTrace();
                }finally{
                    activity.runOnUiThread(new Runnable() {
                        public void run(){
                            Intent intent = new Intent(SplashScreen.this,MainActivity.class);
                            activity.startActivity(intent);
                        }
                    });                       
                }
            }
    ));
    timerThread.start();

Android：WebView应用程序在显示启动画面3秒后崩溃

2 个答案: