java - 带有自定义布局按钮的警报对话框

Question

我有一个警报对话框的布局。并且有一个调用时间选择器的按钮。但我不知道如何编写按钮的setonClickListener。它总是崩溃。

致命异常:主要

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at prototype.feedme.cat.prototype.activity.CatActivity$3.onClick(CatActivity.java:115)
        at android.view.View.performClick(View.java:4756)
        at android.view.View$PerformClick.run(View.java:19749)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5221)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

代码:

private Button time;
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.CatActivity);
    time=(Button)findViewById(R.id.time);
    time.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            TimePickerDialog tpd=new TimePickerDialog(CatActivity.this, mTimesetlistener, mHour, mMinute, true);
            tpd.show();
        }
    });
    clk_btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            AlertDialog alertDialog=new AlertDialog.Builder(CatActivity.this)
                    .setTitle("Hi")
                    .setMessage("Are you ok?")
                    .setView(R.layout.notificaton_setting)
                    .show();
        }
    });
}

Answer 1

您说该按钮位于对话框内。但你试图在 Activity 中找到它。我的意思是，在您尝试显示对话框之前，根本没有按钮，您尝试从 Activity onCreate 方法中找到它。

您需要做的是在对话框 View 中找到您的按钮。你可以这样做:

LayoutInflater inflater = getLayoutInflater();
View dialoglayout = inflater.inflate(R.layout.notificaton_setting, null);
dialogLayout.findViewById(R.id.time).setOnClickListener(...)

AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setView(dialoglayout);
builder.show();