【问题标题】:Error:(44, 20) error: method onCreate(Bundle) is already defined in class MainActivity错误:(44, 20) 错误:方法 onCreate(Bundle) 已在 MainActivity 类中定义
【发布时间】:2016-07-26 10:20:57
【问题描述】:

现在我对 android 开发很陌生。我成功创建了一个简单的 webview 应用程序,它使用 gmap 功能和 maptiler 加载了 gta V 地图。

请看这里:https://youtu.be/qUNEpZbfRDM

但它没有导航等,所以我决定不添加导航抽屉。

这意味着要完成这个应用程序,我只需要一个 webview 功能和导航抽屉。

我尝试过这种方式:使用标准导航抽屉布局创建一个新的应用程序和活动,然后我尝试添加带有地图文件的资产文件夹并将 webview 代码添加到 .java 和 .xml 文件中。虽然我得到了它首先工作,添加 webview 代码给出了一个副本。我在这里和网上搜索了例子,但他们让我很困惑。我可以删除重复的 oncreatebundle 函数并保持原样吗?请检查代码并告诉我我在下面的代码中哪里出错了:

package com.example.serdox.myapplication;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;


 public class MainActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {

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

    WebView browser = (WebView) findViewById(R.id.webview);
    WebSettings webSettings = browser.getSettings();
    webSettings.setJavaScriptEnabled(true);
    browser.loadUrl("file:///android_asset/interactive/map.html");

}

private class MyBrowser extends WebViewClient {
    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        view.loadUrl(url);
        return true;
    }
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
        Snackbar.make(view, "Replace with your own action",     Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

  NavigationView navigationView = (NavigationView)          b           findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
}

@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
  }

  @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();

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

    return super.onOptionsItemSelected(item);
}


  @SuppressWarnings("StatementWithEmptyBody")
  @Override
  public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();

    if (id == R.id.nav_camera) {
        // Handle the camera action
    } else if (id == R.id.nav_gallery) {

    } else if (id == R.id.nav_slideshow) {

    } else if (id == R.id.nav_manage) {

    } else if (id == R.id.nav_share) {

    } else if (id == R.id.nav_send) {

    }

      DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}

【问题讨论】:

  • 你有 2 个 onCreate 方法 man
  • 正如错误所说,您有重复的onCreate(),将其中一个内容移到另一个内容中
  • @serdox 如果有帮助,请勾选它以接受答案
  • @0xDEADC0DE 这对我来说并不容易。对于至少开始的人。不要自大。

标签: java android webview


【解决方案1】:

尝试使用此代码:您已在创建时声明了两次

package com.example.serdox.myapplication;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;


public class MainActivity extends AppCompatActivity
   implements NavigationView.OnNavigationItemSelectedListener {


private class MyBrowser extends WebViewClient {
    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        view.loadUrl(url);
        return true;
    }
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    WebView browser = (WebView) findViewById(R.id.webview);
    WebSettings webSettings = browser.getSettings();
    webSettings.setJavaScriptEnabled(true);
    browser.loadUrl("file:///android_asset/interactive/map.html");

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
        Snackbar.make(view, "Replace with your own action",     Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open,   R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

  NavigationView navigationView = (NavigationView)          b           findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
}

@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
  }

  @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();

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

    return super.onOptionsItemSelected(item);
}


  @SuppressWarnings("StatementWithEmptyBody")
  @Override
  public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();

    if (id == R.id.nav_camera) {
        // Handle the camera action
    } else if (id == R.id.nav_gallery) {

    } else if (id == R.id.nav_slideshow) {

    } else if (id == R.id.nav_manage) {

    } else if (id == R.id.nav_share) {

    } else if (id == R.id.nav_send) {

    }

      DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}

【讨论】:

    【解决方案2】:

    您已在同一个类上定义了两次保护的 void onCreate()。 删除其中一个。

    【讨论】:

    • 这个问题应该被关闭而不是回答。
    • 为什么?这是一个关于新用户看到的可能错误的有效问题。它应该被谷歌索引
    • 我知道我应该删除它,但我不确定它的一部分是什么,什么不是。所以对于一个菜鸟来说,它看起来非常复杂和混乱。
    • 这取决于你想去哪里;-) 阅读代码,试着理解它的作用。
    • 或者,如果您想要反复试验 - 删除一个,运行它,看看这是否是您想要的,如果不是 - 尝试另一个。但我强烈建议您尝试理解。
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