Android Studio开发Todo应用时AlertDialog加载布局无显示问题求助

核心问题原因 #

你创建了AlertDialog.Builder配置实例，但没有调用show()方法让弹窗渲染展示，这是点击按钮后看不到弹窗的直接原因。

修复代码 #

只需要在AlertDialog.Builder配置的最后链式调用show()方法即可，修改后的点击事件代码如下：

imageButton.setOnClickListener(v -> {
    Toast.makeText(MainActivity.this, "Button add clicked ", Toast.LENGTH_SHORT).show();
    LayoutInflater inflater = (LayoutInflater) MainActivity.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View viewInput = inflater.inflate(R.layout.note_input,null,false);

    EditText editTitle = viewInput.findViewById(R.id.edit_text);
    EditText editDescription = viewInput.findViewById(R.id.edit_description);

    new AlertDialog.Builder(MainActivity.this)
            .setView(viewInput)
            .setTitle("Add Note")
            .setPositiveButton("Add", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    String title = editTitle.getText().toString();
                    String description = editDescription.getText().toString();
                    // 可选增加非空判断避免空内容提交
                    if(title.trim().isEmpty()){
                        Toast.makeText(MainActivity.this, "请输入笔记标题", Toast.LENGTH_SHORT).show();
                        return;
                    }
                    Note note = new Note(title,description);
                    boolean isInserted = new NoteHandler(MainActivity.this).create(note);
                    if(isInserted){
                        Toast.makeText(MainActivity.this, "Note saved", Toast.LENGTH_SHORT).show();
                        loadNotes();
                    }
                    else{
                        Toast.makeText(MainActivity.this, "Unable to save the note", Toast.LENGTH_SHORT).show();
                    }
                    dialog.cancel();
                }
            })
            // 新增这行调用show方法展示弹窗
            .show();
});

可选优化项 #

当前自定义布局可以做小调整优化展示效果，避免约束冗余：

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="16dp">

    <EditText
        android:id="@+id/edit_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Note title"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

    <EditText
        android:id="@+id/edit_description"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:hint="Note description"
        app:layout_constraintTop_toBottomOf="@+id/edit_text"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>

调整后根布局高度改为wrap_content更贴合弹窗的展示逻辑，增加内边距避免输入框紧贴弹窗边缘。

内容的提问来源于stack exchange，提问作者Borhen Fatnassi