java - 如何从 fragment 中打开 fragment ？

Question

我制作了一个项目，其中主 Activity 打开 fragment (web.java)，并在(web.java)中添加了一个按钮，当单击它时，它应该打开一个新 fragment (next.java)，但是当我运行应用程序时然后单击按钮应用程序关闭。

主要 Activity 类别

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);
    Button button1 = (Button) findViewById(R.id.button);
    button1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            android.app.FragmentManager fn = getFragmentManager();
            fn.beginTransaction().replace(R.id.content_frame, new web()).addToBackStack( "tag" ).commit();


        }
    }

    );

}

}

WEB类

    public class web extends Fragment {

    View v;

     @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.web_fragment, container, false);

        WebView mWebView = (WebView) v.findViewById(R.id.webView);
        WebSettings webSettings = mWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        String pdf_url = "http://mycbseguide.com/";
        mWebView.loadUrl(pdf_url);
        mWebView.setWebViewClient(new WebViewClient());


        return v;


    }


     @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Button button2 = (Button) v.findViewById(R.id.next);
        button2.setOnClickListener(new View.OnClickListener() {
                                       @Override
                                       public void onClick(View v) {
                                           android.app.FragmentManager fn = getFragmentManager();
                                           fn.beginTransaction().replace(R.id.container, new next()).addToBackStack( "tag" ).commit();


                                       }
                                   }

        );
    }
}

下一个类

public class next extends Fragment {
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.web_fragment, container, false);

    WebView mWebView = (WebView) v.findViewById(R.id.webView);
    WebSettings webSettings = mWebView.getSettings();
    webSettings.setJavaScriptEnabled(true);
    String pdf_url = "http://mycbseguide.com/";
    mWebView.loadUrl(pdf_url);
    mWebView.setWebViewClient(new WebViewClient());


    return v;


}}

日志

08-13 17:33:49.943 30487-30487/com.example.prashant.webview E/dalvikvm: Could not find class 'android.app.SharedElementCallback', referenced from method com.example.prashant.webview.next.access$super
08-13 17:33:49.944 30487-30487/com.example.prashant.webview E/dalvikvm: Could not find class 'android.app.SharedElementCallback', referenced from method com.example.prashant.webview.next.access$super
08-13 17:33:49.953 30487-30487/com.example.prashant.webview E/FragmentManager: No view found for id 0x7f0b0064 (com.example.prashant.webview:id/container) for fragment next{42579268 #0 id=0x7f0b0064}
08-13 17:33:49.954 30487-30487/com.example.prashant.webview E/FragmentManager: Activity state:
08-13 17:33:49.955 30487-30487/com.example.prashant.webview E/FragmentManager:   Local FragmentActivity 4232d178 State:
08-13 17:33:49.956 30487-30487/com.example.prashant.webview E/FragmentManager:     mCreated=truemResumed=true mStopped=false mReallyStopped=false
08-13 17:33:49.956 30487-30487/com.example.prashant.webview E/FragmentManager:     mLoadersStarted=true
08-13 17:33:49.956 30487-30487/com.example.prashant.webview E/FragmentManager:   FragmentManager misc state:
08-13 17:33:49.956 30487-30487/com.example.prashant.webview E/FragmentManager:     mHost=android.support.v4.app.FragmentActivity$HostCallbacks@4232e088
08-13 17:33:49.956 30487-30487/com.example.prashant.webview E/FragmentManager:     mContainer=android.support.v4.app.FragmentActivity$HostCallbacks@4232e088
08-13 17:33:49.956 30487-30487/com.example.prashant.webview E/FragmentManager:     mCurState=5 mStateSaved=false mDestroyed=false
08-13 17:33:49.956 30487-30487/com.example.prashant.webview E/FragmentManager:   View Hierarchy:
08-13 17:33:49.956 30487-30487/com.example.prashant.webview E/FragmentManager:     com.android.internal.policy.impl.PhoneWindow$DecorView{42346278 V.E..... ... 0,0-720,1184}
08-13 17:33:49.956 30487-30487/com.example.prashant.webview E/FragmentManager:       android.widget.LinearLayout{42347638 V.E..... ... 0,0-720,1184}
08-13 17:33:49.956 30487-30487/com.example.prashant.webview E/FragmentManager:         android.view.ViewStub{4234e8c8 G.E..... ... 0,0-0,0 #1020312}
08-13 17:33:49.957 30487-30487/com.example.prashant.webview E/FragmentManager:         android.widget.FrameLayout{4234ecf8 V.E..... ... 0,50-720,1184}
08-13 17:33:49.957 30487-30487/com.example.prashant.webview E/FragmentManager:           android.support.v7.widget.ActionBarOverlayLayout{42353468 V.ED.... ... 0,0-720,1134 #7f0b0043 app:id/decor_content_parent}
08-13 17:33:49.957 30487-30487/com.example.prashant.webview E/FragmentManager:             android.support.v7.widget.ContentFrameLayout{423566b8 V.ED.... ... 0,112-720,1134 #1020002 android:id/content}
08-13 17:33:49.957 30487-30487/com.example.prashant.webview E/FragmentManager:               
08-13 17:33:49.959 30487-30487/com.example.prashant.webview E/FragmentManager: android.widget.RelativeLayout{4236d1a8 V.E..... ... 0,0-720,1022 #7f0b0054 app:id/content_frame}
08-13 17:33:49.959 30487-30487/com.example.prashant.webview E/FragmentManager:                 android.support.v7.widget.AppCompatButton{4236dd78 VFED..C. ... 272,463-448,559 #7f0b0055 app:id/button}
08-13 17:33:49.959 30487-30487/com.example.prashant.webview E/FragmentManager:             android.support.v7.widget.ActionBarContainer{42358c68 V.ED.... ... 0,0-720,112 #7f0b0044 app:id/action_bar_container}
08-13 17:33:49.959 30487-30487/com.example.prashant.webview E/FragmentManager:               android.support.v7.widget.Toolbar{423593e0 V.E..... ... 0,0-720,112 #7f0b0045 app:id/action_bar}
08-13 17:33:49.959 30487-30487/com.example.prashant.webview E/FragmentManager:                 android.widget.TextView{4236a558 V.ED.... ... 32,29-193,83}
08-13 17:33:49.959 30487-30487/com.example.prashant.webview E/FragmentManager:                 android.support.v7.widget.ActionMenuView{42384790 V.E..... ... 720,0-720,112}
08-13 17:33:49.959 30487-30487/com.example.prashant.webview E/FragmentManager:               android.support.v7.widget.ActionBarContextView{42363178 G.E..... ... 0,0-0,0 #7f0b0046 app:id/action_context_bar}
08-13 17:33:49.963 30487-30487/com.example.prashant.webview E/AndroidRuntime: FATAL EXCEPTION: main
                                                                              Process: com.example.prashant.webview, PID: 30487
                                                                              java.lang.IllegalArgumentException: No view found for id 0x7f0b0064 (com.example.prashant.webview:id/container) for fragment next{42579268 #0 id=0x7f0b0064}
`                                                                                  at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:882)

`

                                                                                  at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
                                                                                  at android.app.BackStackRecord.run(BackStackRecord.java:698)
                                                                                  at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1447)
                                                                                  at android.app.FragmentManagerImpl$1.run(FragmentManager.java:443)
                                                                                  at android.os.Handler.handleCallback(Handler.java:808)
                                                                                  at android.os.Handler.dispatchMessage(Handler.java:103)
                                                                                  at android.os.Looper.loop(Looper.java:193)
                                                                                  at android.app.ActivityThread.main(ActivityThread.java:5345)
                                                                                  at java.lang.reflect.Method.invokeNative(Native Method)
                                                                              at java.lang.reflect.Method.invoke(Method.java:515)
                                                                                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:828)
                                                                                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:644)
                                                                                  at dalvik.system.NativeStart.main(Native Method)
08-13 17:33:49.943 30487-30487/com.example.prashant.webview E/dalvikvm: Could not find class 'android.app.SharedElementCallback', referenced from method com.example.prashant.webview.next.access$super

Answer 1

只需在主布局的底部添加 LinearLayout 即可，如下所示，

之后只需添加这样的 fragment ，

android.app.FragmentManager fn = getFragmentManager();
fn.beginTransaction().add(R.id.content_frame, new web()).addToBackStack("tag").commit();