我想显示一个对话框/弹出窗口,向用户显示一条消息“您确定要删除此条目吗?”,其中一个按钮说“删除”。当点击Delete时,它应该删除该条目,否则什么都不删除。

我已经为这些按钮写了一个点击监听器,但我如何调用对话框或弹出窗口及其功能?


当前回答

对我来说

new AlertDialog.Builder(this)
    .setTitle("Closing application")
    .setMessage("Are you sure you want to exit?")
    .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
          @Override
          public void onClick(DialogInterface dialog, int which) {

          }
     }).setNegativeButton("No", null).show();

其他回答

您可以为此使用AlertDialog,并使用它的Builder类构造一个AlertDialog。下面的例子使用默认的构造函数,它只接受Context,因为对话框将从传入的Context继承适当的主题,但是如果你想这样做,还有一个构造函数允许你指定一个特定的主题资源作为第二个参数。

new AlertDialog.Builder(context)
    .setTitle("Delete entry")
    .setMessage("Are you sure you want to delete this entry?")

    // Specifying a listener allows you to take an action before dismissing the dialog.
    // The dialog is automatically dismissed when a dialog button is clicked.
    .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int which) { 
            // Continue with delete operation
        }
     })

    // A null listener allows the button to dismiss the dialog and take no further action.
    .setNegativeButton(android.R.string.no, null)
    .setIcon(android.R.drawable.ic_dialog_alert)
    .show();
// Dialog box

public void dialogBox() {
    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
    alertDialogBuilder.setMessage("Click on Image for tag");
    alertDialogBuilder.setPositiveButton("Ok",
        new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface arg0, int arg1) {
        }
    });

    alertDialogBuilder.setNegativeButton("cancel",
        new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface arg0, int arg1) {

        }
    });

    AlertDialog alertDialog = alertDialogBuilder.create();
    alertDialog.show();
}

使用Anko (Kotlin开发人员的官方库),您可以简单地使用

alert("Alert title").show()

或者更复杂的:

alert("Hi, I'm Roy", "Have you tried turning it off and on again?") {
    yesButton { toast("Oh…") }
    noButton {}
}.show()

导入Anko:

implementation "org.jetbrains.anko:anko:0.10.8"

这是在kotlin中完成的

val builder: AlertDialog.Builder = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            AlertDialog.Builder(this, android.R.style.Theme_Material_Dialog_Alert)
        } else {
            AlertDialog.Builder(this)
        }
        builder.setTitle("Delete Alert!")
                .setMessage("Are you want to delete this entry?")
                .setPositiveButton("YES") { dialog, which ->

                }
                .setNegativeButton("NO") { dialog, which ->

                }
                .setIcon(R.drawable.ic_launcher_foreground)
                .show()

现在与Jetpack撰写引入android,你可以简单地创建警报对话框使用下面的代码

if (viewModel.shouldDialogOpen.value) {

        AlertDialog(onDismissRequest = { viewModel.shouldDialogOpen.value = false },
            title = { Text("Delete Entry?") },
            text = {
                Text("Are you sure you want to delete this entry?")
            },
            dismissButton = {
                Button(modifier = Modifier.fillMaxWidth(), onClick = {
                    viewModel.shouldDialogOpen.value = false
                }) {
                    Text(text = "Cancel")
                }
            }, confirmButton = {
                Button(modifier = Modifier.fillMaxWidth(), onClick = {
                    viewModel.shouldDialogOpen.value = false
                    viewModel.beginDelete(recipe)
                }) {
                    Text(text = "Okay")
                }
            })
    }

在viewModel中。shouldDialogOpen, shouldDialogOpen是viewmodel中的一个mutablestate字段,当我们需要显示或解散对话框时,我们会改变它的值。

更多的代码样本Jetpack撰写:- https://androidlearnersite.wordpress.com/2021/08/03/jetpack-compose-1-0-0-sample-codes/