android - 根据 UserType 从 ListView 中隐藏按钮
问题描述
我有一个登录页面，当用户登录时，它会将他重定向到包含图像、按钮和文本视图的 ListViewAct。
重定向后，我创建了一个 if 条件来检查登录的用户类型是管理员还是普通用户。
我有三个按钮（添加、编辑、删除）我想对普通用户隐藏这些按钮。
我尝试将这些按钮的可见性设置为GONE，但结果在调试时没有任何反应，并且这些按钮仍然为普通用户显示。
MainAct代码：
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private Button btn_add,btn_edit,btn_delete=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = getIntent();
String username = intent.getStringExtra("Username");
String password = intent.getStringExtra("Password");
btn_add = findViewById(R.id.btn_add);
btn_edit = findViewById(R.id.btn_edit);
btn_delete = findViewById(R.id.btn_delete);
if(username.equals("admin") && password.equals("admin")){
Log.d(TAG, "onCreate: Started.");
ListView listView = (ListView) findViewById(R.id.li_view);
ArrayList<PersonInfo> students = new ArrayList<>();
students.add(new PersonInfo(android.R.drawable.btn_star, "test", "03/27/1998"));
StudentsListAdapter studentsListAdapter = new StudentsListAdapter(
this, R.layout.adapter_view_layout, students);
listView.setAdapter(studentsListAdapter);
}
else if (username.equals("user") && password.equals("user"))
{
ListView listView = (ListView) findViewById(R.id.li_view);
ArrayList<PersonInfo> students = new ArrayList<>();
students.add(new PersonInfo(android.R.drawable.btn_star, "test", "03/27/1998"));
StudentsListAdapter studentsListAdapter = new StudentsListAdapter(
this, R.layout.adapter_view_layout, students);
listView.setAdapter(studentsListAdapter);
if (btn_add != null && btn_edit !=null && btn_delete !=null){
btn_add.setVisibility(View.GONE);
btn_edit.setVisibility(View.GONE);
btn_delete.setVisibility(View.GONE);
}
}
}
}
列表适配器代码：
public class StudentsListAdapter extends ArrayAdapter<PersonInfo> {
private Context contxt;
private int rsrc;
private List<PersonInfo> persons;
public StudentsListAdapter( Context context, int resource, List<PersonInfo> _persons) {
super(context, resource, _persons);
contxt = context;
rsrc = resource;
persons=_persons;
}
@NonNull
@Override
public View getView(final int position, @Nullable View convertView, @NonNull ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(contxt);
View view = inflater.inflate(rsrc, null,false);
ImageView imageView = view.findViewById(R.id.imgP);
TextView pName = view.findViewById(R.id.txtView2);
TextView pBirthday = view.findViewById(R.id.txtView3);
PersonInfo p = persons.get(position);
imageView.setImageDrawable(contxt.getResources().getDrawable(p.getImage()));
pBirthday.setText(p.getBirthday());
pName.setText(p.getName());
return view;
}
}
列表视图 XML：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:padding="15dp"
android:layout_height="match_parent"
android:weightSum="100" >
<ImageView
android:id="@+id/imgP"
android:layout_width="399dp"
android:layout_height="150dp"
android:layout_weight="66.6" />
<RelativeLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="33.3">
<TextView
android:gravity="center"
android:text="TextView2"
android:layout_width="match_parent"
android:layout_height="30dp"
android:id="@+id/txtView2"/>
<TextView
android:id="@+id/txtView3"
android:layout_width="match_parent"
android:layout_height="30dp"
android:layout_below="@+id/txtView2"
android:gravity="center"
android:text="TextView3" />
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent" />
<Button
android:id="@+id/btn_add"
android:layout_width="69dp"
android:layout_height="wrap_content"
android:layout_below="@+id/txtView3"
android:layout_marginRight="20dp"
android:text="ADD" />
<Button
android:layout_width="69dp"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/btn_add"
android:layout_below="@id/txtView3"
android:id="@+id/btn_edit"
android:text="edit"/>
<Button
android:layout_width="80dp"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/btn_edit"
android:layout_below="@+id/txtView3"
android:id="@+id/btn_delete"
android:text="Delete"/>
</RelativeLayout>
</LinearLayout>
主要 XML：
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
tools:context=".MainActivity">
<ListView
android:id="@+id/li_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
tools:layout_algignParentStart="true" />
</androidx.constraintlayout.widget.ConstraintLayout>
个人信息类：
public class PersonInfo {
private int image;
private String name;
private String birthday;
public PersonInfo(int image, String name, String birthday) {
this.image = image;
this.name = name;
this.birthday = birthday;
}
public String getName(){
return name;
}
public int getImage() {
return image;
}
public void setName(String name) {
this.name = name;
}
public String getBirthday() {
return birthday;
}
public void setBirthday(String birthday) {
this.birthday = birthday;
}
}
我没有对 ListAdapter 上的按钮进行任何更改。
我做错了什么？任何帮助将不胜感激。
谢谢！
解决方案
根据你xml的buttons在里面ListView的项目。所以，你必须在里面处理它adapter而不是在fragment. 检查以下：
public class StudentsListAdapter extends ArrayAdapter<PersonInfo> {
private Context contxt;
private int rsrc;
private List<PersonInfo> persons;
private boolean isAdmin;
public StudentsListAdapter( Context context, int resource, List<PersonInfo> _persons, boolean _isAadmin) {
super(context, resource, _persons);
contxt = context;
rsrc = resource;
persons=_persons;
isAdmin = _isAadmin;
}
@NonNull
@Override
public View getView(final int position, @Nullable View convertView, @NonNull ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(contxt);
View view = inflater.inflate(rsrc, null,false);
ImageView imageView = view.findViewById(R.id.imgP);
TextView pName = view.findViewById(R.id.txtView2);
TextView pBirthday = view.findViewById(R.id.txtView3);
Button btn_add = view.findViewById(R.id.btn_add);
Button btn_edit = view.findViewById(R.id.btn_edit);
Button btn_delete = view.findViewById(R.id.btn_delete);
if(isAdmin) {
btn_add.setVisibility(View.VISIBLE);
btn_edit.setVisibility(View.VISIBLE);
btn_delete.setVisibility(View.VISIBLE);
} else {
btn_add.setVisibility(View.GONE);
btn_edit.setVisibility(View.GONE);
btn_delete.setVisibility(View.GONE);
}
PersonInfo p = persons.get(position);
imageView.setImageDrawable(contxt.getResources().getDrawable(p.getImage()));
pBirthday.setText(p.getBirthday());
pName.setText(p.getName());
return view;
}
}
然后修改你fragment的调用adapter如下：
ListView listView = (ListView) findViewById(R.id.li_view);
ArrayList<PersonInfo> students = new ArrayList<>();
students.add(new PersonInfo(android.R.drawable.btn_star, "test", "03/27/1998"));
if(username.equals("admin") && password.equals("admin")){
StudentsListAdapter studentsListAdapter = new StudentsListAdapter(
this, R.layout.adapter_view_layout, students, true); // true -> admin user
} else if (username.equals("user") && password.equals("user")) {
StudentsListAdapter studentsListAdapter = new StudentsListAdapter(
this, R.layout.adapter_view_layout, students, false); // false -> normal user
}
listView.setAdapter(studentsListAdapter);
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