Question

我尝试在三种情况下更改片段活动中的TextView，但我无法更改TextView 是否有任何解决方案可以在自己的Fragment_Activity或Main_Activity中更改Fragment的TextView？

Fragment.java

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }


        TextView textView = (TextView) getView().findViewById(R.id.textView1);
        textView.setText("Done!");
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_blank_fragment2, container, false);
        TextView tv = (TextView) view.findViewById(R.id.textView1);
        tv.setText("Done!");
        return view;
    }

    @Override
    public void onActivityCreated (Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        TextView tv = (TextView) getView().findViewById(R.id.textView1);
        tv.setText("Done!");
    }

fragment.xml之

...
 <TextView
        android:textColor="@color/myBlack"
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="test"
        android:textAppearance="?android:attr/textAppearanceMedium"
        />
....

在MainActivity中调用视图的片段类：

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_weixin);

        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
        instance = this;

...

 View view2 = mLi.inflate(R.layout.fragment_blank_fragment2, null);
           views.add(view2);
...
}

Answer 1

因为我们无法看到整个Fragment.xml文件或主要活动的xml，所以无法确定问题是什么，但似乎您可能没有在Fragment.xml中指定片段类文件所以oncreate永远不会被调用。我建议您在main_weixin xml中添加片段属性，并删除主活动中的view2通货膨胀，然后只需将其添加到main_weixin.xml：

<fragment
    android:name="your_package_name.Fragment"
    android:id="@+id/fragment_id"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

Answer 2

要知道

片段getView()的onCreate返回null，因为仍然在未创建的视图中。
在片段中创建一个方法，使用片段实例从活动中设置TextView的值。

示例：片段

public class Fragment1 extends Fragment {


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

        View view = inflater.inflate(R.layout.fragment_blank_fragment2, container, false);
        tv = (TextView) view.findViewById(R.id.textView1);
        tv.setText("Done!");
        return view;

    }

    public void setViewText(String text){
        tv.setText(text);
    }
}

活动

public class MyActivity extends FragmentActivity {

    Fragment1 fragment1;

    @Override
    protected void onCreate(Bundle arg0) {
        super.onCreate(arg0);
        setContentView(R.layout.activity_fragment);
        //as you are using static fragment so create fragment instance using findFragmentById(id)
        fragment1 = (Fragment1) getSupportFragmentManager().findFragmentById(R.id.fragment1);

        fragment1.setViewText("Message");

    }
}

访问官方文档Communicating with Other Fragments

如何使用自己的java类更改片段textview？

2 个答案: