Question

这就是我显示两次的意思。它们都可以根据您放置手指的位置滚动。

我有一个基本的适配器，除了加载视图（上面有一些占位符数据）之外什么都不做。

以下是适配器中引用视图的地方：

pyplot.figure(figsize=(5,5))
images = create_dummy_images()

for i, image in enumerate(images):
    pyplot.subplot(2, 2, i + 1)
    pyplot.axis("off")
    pyplot.imshow(image, aspect='auto')

pyplot.subplots_adjust(hspace=0, wspace=0)
pyplot.show()

适配器在这里调用一个片段：

    @Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
    View view = LayoutInflater.from(context).inflate(R.layout.list_item_forecast, parent, false);

    return view;
}

我在该片段中还有一个游标加载器，用于将游标交换到LoadFinished和onLoaderReset。

我的layout.xml文件，以防它相关。

    @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_main, container, false);

    mForecastAdapter = new ForecastAdapter(getActivity(), null, 0);


    ListView forecastListView = (ListView) rootView.findViewById(R.id.listView_forecast);
    forecastListView.setAdapter(mForecastAdapter);

    forecastListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView adapterView, View view, int position, long l) {
            // CursorAdapter returns a cursor at the correct position for getItem(), or null
            // if it cannot seek to that position.
            Cursor cursor = (Cursor) adapterView.getItemAtPosition(position);
            if (cursor != null) {
                String locationSetting = Utility.getPreferredLocation(getActivity());
                Intent intent = new Intent(getActivity(), DetailActivity.class)
                        .setData(WeatherContract.WeatherEntry.buildWeatherLocationWithDate(
                                locationSetting, cursor.getLong(COL_WEATHER_DATE)
                        ));
                startActivity(intent);
            }
        }
    });

    return rootView;
}

要求我的MainActivity.java：

<?xml version="1.0" encoding="utf-8"?>

<!-- Layout for weather forecast list item for future day (not today) -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical"
    android:minHeight="?android:attr/listPreferredItemHeight"
    android:orientation="horizontal"
    android:padding="16dp">

    <ImageView
        android:id="@+id/list_item_icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@mipmap/ic_launcher"/>

    <LinearLayout
        android:layout_height="wrap_content"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:orientation="vertical"
        android:paddingLeft="16dp">

        <TextView
            android:id="@+id/list_item_date_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Tomorrow"/>

        <TextView
            android:id="@+id/list_item_forecast_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Clear"/>

    </LinearLayout>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <TextView
            android:id="@+id/list_item_high_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="81"/>

        <TextView
            android:id="@+id/list_item_low_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="68"/>
    </LinearLayout>

</LinearLayout>

这是main_activity.xml

public class MainActivity extends AppCompatActivity {

    String LOG_TAG = MainActivity.class.getSimpleName();

    private final String FORECASTFRAGMENT_TAG = "FFTAG";
    String mLocation;


    private void showMap(Uri zipCode){
        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setData(zipCode);

        if(intent.resolveActivity(this.getPackageManager()) != null){
            startActivity(intent);
        }else{
            View view = getCurrentFocus();
            Snackbar.make(view, "No Map application found", Snackbar.LENGTH_SHORT).setAction("", null).show();
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
//        super.onCreate(savedInstanceState);
//        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
//
//        mLocation = Utility.getPreferredLocation(this);
//
//        Log.v(LOG_TAG, "onCreate()");

        mLocation = Utility.getPreferredLocation(this);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.fragment, new ForecastFragment(), FORECASTFRAGMENT_TAG)
                    .commit();
        }

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.v(LOG_TAG, "onDestroy()");
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.v(LOG_TAG, "onStart()");
    }

    @Override
    protected void onResume() {
        super.onResume();
        if(mLocation != Utility.getPreferredLocation(this)){
            mLocation = Utility.getPreferredLocation(this);
            ForecastFragment ff  = (ForecastFragment)getSupportFragmentManager().findFragmentByTag(FORECASTFRAGMENT_TAG);
            ff.onLocationChange();
        }
        Log.v(LOG_TAG, "onResume()");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.v(LOG_TAG, "onStop()");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.v(LOG_TAG, "onPause()");
    }

    @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.

        Context context = getApplicationContext();
//        int duration = Toast.LENGTH_SHORT;
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
//            Toast toast = Toast.makeText(context, "Settings Pressed", duration);
//            toast.show();

            Intent intent = new Intent(context, SettingsActivity.class);
            startActivity(intent);

            return true;
        }else if(id == R.id.action_map_view){
            SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getApplication());
            String zipCode = preferences.getString(getString(
                    R.string.pref_location_key),
                    getString(R.string.pref_location_default));


            Uri geolocation = Uri.parse("geo:0,0?").buildUpon()
                    .appendQueryParameter("q", zipCode)
                    .build();

            showMap(geolocation);
        }

        return super.onOptionsItemSelected(item);
    }
}

这是引用的content_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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:fitsSystemWindows="true"
    tools:context="com.example.android.sunshine.app.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

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

    <include layout="@layout/content_main" />

    <!--<android.support.design.widget.FloatingActionButton-->
        <!--android:id="@+id/fab"-->
        <!--android:layout_width="wrap_content"-->
        <!--android:layout_height="wrap_content"-->
        <!--android:layout_gravity="bottom|end"-->
        <!--android:layout_margin="@dimen/fab_margin"-->
        <!--android:src="@android:drawable/ic_dialog_email" />-->

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

Answer 1

我之前已经看过片段之前的这种行为。它表示您有多个已附加到活动的片段。每个都有自己的功能列表视图。我不确定你的代码中是如何发生这种情况的。

修改

以下地方附有两个碎片。

进入你的xml：

<fragment 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:id="@+id/fragment" android:name="com.example.android.sunshine.app.ForecastFragment" android:layout_width="match_parent" android:layout_height="match_parent" app:layout_behavior="@string/appbar_scrolling_view_behavior" tools:layout="@layout/fragment_main" />

一旦进入您的活动：

getSupportFragmentManager().beginTransaction() .add(R.id.fragment, new ForecastFragment(), FORECASTFRAGMENT_TAG) .commit();

要解决此问题，请删除

getSupportFragmentManager().beginTransaction() .add(R.id.fragment, new ForecastFragment(), FORECASTFRAGMENT_TAG) .commit();

在您的onCreate()活动中，您现在只会显示一个列表。

Answer 2

您不需要在onCreate中添加片段，因为您已在xml中声明了它：

从onCreate

中删除此内容

  if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.fragment, new ForecastFragment(),FORECASTFRAGMENT_TAG)
                .commit();
    }

并且这样做：

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

    mLocation = Utility.getPreferredLocation(this);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

}

Android视图显示两次

2 个答案: