Question

我对Android有点新，所以请原谅任何缺点。

我在activity_main.xml中有一个FloatingActionButton，无论何时点击它，我都希望它带我到一个带有两个EditText字段的新活动，还有另一个FAB。
我想要做的是，无论何时输入文本并按下activity_new_goal.xml中的FAB，它都应该创建一个包含@+id/edit_goalTitle文本中文本的RecyclerView。它显示了return data;中不兼容类型的错误，并显示无法解析getData()

中的方法MainActivity.java

这是我的代码：

MainActivity.java：

public class MainActivity extends AppCompatActivity {

private Toolbar toolbar;
private RVAdapter adapter;
private RecyclerView recyclerView;
private EditText editGoalTitle;
private String stringGoalTitle;

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

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

    getSupportActionBar().setDisplayShowHomeEnabled(true);
    NavigationDrawerFragment drawerFragment = (NavigationDrawerFragment) getSupportFragmentManager().findFragmentById(R.id.fragment_navigation_drawer);
    drawerFragment.setUp(R.id.fragment_navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout), (Toolbar) findViewById(R.id.app_bar));

    recyclerView = (RecyclerView) findViewById(R.id.goalList);
    recyclerView.setHasFixedSize(true);
    adapter = new RVAdapter(getApplicationContext(), getData());
    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));



}

public RVData mSetRecyclerGoalTitle(View view) {

    editGoalTitle = (EditText) findViewById(R.id.edit_goalTitle);
    editGoalTitle.setText(R.string.dummyTxt);
    stringGoalTitle = editGoalTitle.getText().toString();


    public List<RVData> getData () {
        List<RVData> data = new ArrayList<>();
        String[] titles = {};
        if (stringGoalTitle != null) {
            titles = new String[]{stringGoalTitle};
        } else {
            titles = new String[]{"DummyText1"};
        }
        for (int i = 0; i <= titles.length; i++) {
            RVData current = new RVData();
            current.goalTitle = titles[i];
            data.add(current);
        }
        return data;
    }
}

public void newGoal(View view) {
    Intent intent = new Intent(MainActivity.this, NewGoal.class);
    startActivity(intent);
}

@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);
}
}

RVData.java：

import android.widget.CheckBox;

public class RVData {
CheckBox checkBox;
String goalTitle;

}

RVAdapter.java：

public class RVAdapter extends RecyclerView.Adapter<RVAdapter.myViewHolder> {

List<RVData> data = Collections.emptyList();
private LayoutInflater inflater;

public RVAdapter(Context context, List<RVData> data) {
    inflater = LayoutInflater.from(context);
    this.data = data;
}

@Override
public myViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    View view = inflater.inflate(R.layout.goal_row, viewGroup, false);
    myViewHolder holder = new myViewHolder(view);
    return holder;
}

@Override
public void onBindViewHolder(myViewHolder viewHolder, int position) {
    RVData current = data.get(position);
    viewHolder.title.setText(current.goalTitle);

}

@Override
public int getItemCount() {
    return data.size();
}

class myViewHolder extends RecyclerView.ViewHolder {
    //@Bind(R.id.goalRowTitle)
    TextView title;
    //@Bind(R.id.goalRowCB)
    CheckBox checkBox;

    public myViewHolder(View itemView) {
        super(itemView);
        title = (TextView) itemView.findViewById(R.id.goalRowTitle);
        checkBox = (CheckBox) itemView.findViewById(R.id.goalRowCB);
    }
}
}

activity_main.xml：

<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"
style="@style/DefaultLayoutStyle"
tools:context=".MainActivity">

<include
    android:id="@+id/app_bar"
    layout="@layout/app_bar" />


<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    style="@style/FABStyle"
    android:onClick="newGoal"
    android:src="@drawable/ic_add"
    app:borderWidth="0dp" />

<android.support.v4.widget.DrawerLayout
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@id/app_bar">

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/goalList"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center"></android.support.v7.widget.RecyclerView>
    </RelativeLayout>

    <fragment
        android:id="@+id/fragment_navigation_drawer"
        android:name="com.kellarapps.zeal.NavigationDrawerFragment"
        android:layout_width="@dimen/nav_drawer_width"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:layout="@layout/fragment_navigation_drawer"
        tools:layout="@layout/fragment_navigation_drawer" />

</android.support.v4.widget.DrawerLayout>

activity_new_goal.xml：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
style="@style/DefaultLayoutStyle"
tools:context="com.kellarapps.zeal.NewGoal">

<include
    android:id="@+id/app_bar"
    layout="@layout/app_bar" />

<LinearLayout
    android:id="@+id/goalTitle"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/app_bar"
    android:layout_marginTop="10dp"
    android:orientation="horizontal"
    android:paddingEnd="5dp"
    android:paddingLeft="5dp"
    android:paddingRight="5dp"

    android:paddingStart="5dp">

    <TextView
        style="@style/DefaultTVStyle"
        android:text="@string/goal" />

    <EditText
        android:id="@+id/edit_goalTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/goalHint" />
</LinearLayout>

<LinearLayout
    android:id="@+id/goalDescription"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/goalTitle"
    android:layout_marginTop="10dp"
    android:orientation="horizontal"
    android:paddingEnd="5dp"
    android:paddingLeft="5dp"
    android:paddingRight="5dp"
    android:paddingStart="5dp">

    <TextView
        style="@style/DefaultTVStyle"
        android:text="@string/goalDescription" />

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/description"
        android:maxLines="3" />

</LinearLayout>

<android.support.design.widget.FloatingActionButton
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/fab2"
    style="@style/FABStyle"
    android:onClick="mSetRecyclerGoalTitle"
    android:src="@drawable/ic_action_done"
    app:borderWidth="0dp"/>

NewGoal.java：

public class NewGoal extends AppCompatActivity {

private Toolbar toolbar;

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

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

    getSupportActionBar().setHomeButtonEnabled(true);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

}

@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_new_goal, 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;
    }

    if(id == android.R.id.home)
    {
        NavUtils.navigateUpFromSameTask(this);
    }
    return super.onOptionsItemSelected(item);
}
}

goal_row.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:orientation="horizontal"
android:paddingLeft="10dp"
android:paddingStart="10dp">

<CheckBox
    android:id="@+id/goalRowCB"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/goalRowTitle"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:clickable="true"
    android:gravity="center_horizontal"
    android:text="@string/dummyTxt"
    android:textColor="@color/TextColor"
    android:textSize="17sp" />

Answer 1

从我看到的，您尝试做的是将 NewGoal 活动中的一些信息返回到 MainActivity 。您无法访问其他活动的布局以恢复其视图的内容。

通常使用 startActivityForResult 完成。

看看开发人员参考： http://developer.android.com/training/basics/intents/result.html

Answer 2

更改

public RVData mSetRecyclerGoalTitle(View view) {

    editGoalTitle = (EditText) findViewById(R.id.edit_goalTitle);
    editGoalTitle.setText(R.string.dummyTxt);
    stringGoalTitle = editGoalTitle.getText().toString();


    public List<RVData> getData () {
        List<RVData> data = new ArrayList<>();
        String[] titles = {};
        if (stringGoalTitle != null) {
            titles = new String[]{stringGoalTitle};
        } else {
            titles = new String[]{"DummyText1"};
        }
        for (int i = 0; i <= titles.length; i++) {
            RVData current = new RVData();
            current.goalTitle = titles[i];
            data.add(current);
        }
        return data;
    }
}

到

public void mSetRecyclerGoalTitle(View view) {

    editGoalTitle = (EditText) findViewById(R.id.edit_goalTitle);
    editGoalTitle.setText(R.string.dummyTxt);
    stringGoalTitle = editGoalTitle.getText().toString();

}

public List<RVData> getData () {
    mSetRecyclerGoalTitle(null);
    List<RVData> data = new ArrayList<>();
    String[] titles = {};
    if (stringGoalTitle != null) {
        titles = new String[]{stringGoalTitle};
    } else {
        titles = new String[]{"DummyText1"};
    }

    for (int i = 0; i <= titles.length; i++) {
        RVData current = new RVData();
        current.goalTitle = titles[i];
        data.add(current);
    }
    return data;
}

Answer 3

您的代码存在许多问题。

首先，这种方法没有任何意义：

public RVData mSetRecyclerGoalTitle(View view) {

editGoalTitle = (EditText) findViewById(R.id.edit_goalTitle);
editGoalTitle.setText(R.string.dummyTxt);
stringGoalTitle = editGoalTitle.getText().toString();


public List<RVData> getData () {
    List<RVData> data = new ArrayList<>();
    String[] titles = {};
    if (stringGoalTitle != null) {
        titles = new String[]{stringGoalTitle};
    } else {
        titles = new String[]{"DummyText1"};
    }
    for (int i = 0; i <= titles.length; i++) {
        RVData current = new RVData();
        current.goalTitle = titles[i];
        data.add(current);
    }
        return data;
    }
}

第一行出错了。 edit_goalTitle不是来自activity_main，因此您无法找到该视图。

接下来你在方法中写了一个方法定义？不，那不会发生。这就是IDE为您提供错误的原因。

然后你在xml中声明了onClick：

android:onClick="mSetRecyclerGoalTitle"

但是，这个onClick事情也会失败，因为MainActivity夸大了其他xml文件，而不是activity_new_goal.xml。只有将mSetRecyclerGoalTitle方法放在导致activity_new_goal.xml膨胀的活动中时，此方法才有效。

Answer 4

在方法定义中，()与方括号public List<RVData> getData () { ... }之间有空格：

public List<RVData> getData() {  // <-- deleted space
    ...
}

更改为：

library(ggplot2)
library(dplyr)
library(gridExtra)

x <- data.frame(Var = rep(1:3, 10000)) %>%
  mutate(Val = rnorm(10000)*Var,
         Var = factor(Var)) %>%
  arrange(Var, Val) %>%
  group_by(Var) %>%
  mutate(ecdf = ecdf(Val)(Val))

ggplot(x, aes(x=Val)) + 
  stat_ecdf(aes(color = Var), size = 1.25, alpha = .9) -> gg1

ggplot(x, aes(x=Val)) + 
  stat_ecdf(aes(color = Var), size = 1.35, alpha = .9) +
  guides(color = guide_legend(override.aes= list(alpha = 1))) -> gg2

grid.arrange(gg1, gg2)

点击按钮时出现新的RecyclerView项目

4 个答案: