Question

我的代码如下

带有4个Edittext的警告对话框的布局

alert_edit_information1.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Name"
    android:id="@+id/editTextInformationName" />

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Address"
    android:id="@+id/editTextInformationAddress" />

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Phone"
    android:id="@+id/editTextInformationPhones"
    android:layout_gravity="center_horizontal" />

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Company Name"
    android:id="@+id/editTextInformationCompanyName" />

单击相对布局以弹出警告对话框

 relativeLayout1.setOnClickListener(new AdapterView.OnClickListener() {
        @Override
        public void onClick(View v) {
AlertDialog.Builder alert = new AlertDialog.Builder(getContext());
             alert.setTitle("Alert Dialog With EditText"); //Set Alert dialog title
             alert.setView(R.layout.alert_edit_information1);//Set 4 edittext to alert dialog
             editTextName = (EditText) v.findViewById(R.id.editTextInformationName); //error posible here
             editTextName.setText("Name here",TextView.BufferType.EDITABLE); //error here
             alert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {  } 
            }); //End of alert.setPositiveButton
alert.setNegativeButton("CANCEL", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int whichButton) {
                            // Canceled.
                            dialog.cancel();
                        }
                    });//End of alert.setNegativeButton
                    AlertDialog alertDialog = alert.create();
                    alertDialog.show();

    }
        });

错误日志

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setText(java.lang.CharSequence, android.widget.TextView$BufferType)' on a null object reference

我是否正确初始化EditText？这条线路好吗？

editTextName =（EditText）v.findViewById（R.id.editTextInformationName）;

Answer 1

<强>唐＆＃39;吨

  editTextName = (EditText) v.findViewById(R.id.editTextInformationName);
  editTextName.setText("Name here",TextView.BufferType.EDITABLE);

<强>不要

您应该传递View的对象。

 editTextName = (EditText) alert.findViewById(R.id.editTextInformationName);
 editTextName.setText("Name here");

Answer 2

你已经完成了以下的工作。

AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);
// ...Irrelevant code for customizing the buttons and title
LayoutInflater inflater = this.getLayoutInflater();
View dialogView = inflater.inflate(R.layout. alert_edit_information1, null);
dialogBuilder.setView(dialogView);

EditText editText = (EditText) dialogView.findViewById(R.id.editTextInformationName);
editText.setText("test label");
AlertDialog alertDialog = dialogBuilder.create();
alertDialog.show();

Answer 3

不要直接设置AlertDialog的视图，如

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2\video\tracking.hpp>

#include <cmath>
#include <string>  
#include <iostream>  
#include <sstream>  
#include <filesystem> 
#include <cstring>


int main(int argc, char *argv[])
{

    //Tracking of points of interest:
    cv::Mat img;
    cv::UMat prevgray;

    std::vector<cv::Point2f> featuresPrevious;
    std::vector<cv::Point2f> featuresCurrent;
    //int count = 0;



    for (auto& p : std::experimental::filesystem::directory_iterator("C:\\Billeder"))
    {
        img = cv::imread(p.path().string(), CV_LOAD_IMAGE_GRAYSCALE);

        //printf("Image number: %d\n", count);
        //count++;

        if (prevgray.empty() == false)
        {
            std::vector<cv::Point2f> featuresNextPos;
            std::vector<uchar> featuresFound;
            cv::Mat err;


            featuresPrevious = std::move(featuresCurrent);
            // create points of interest in current image:
            goodFeaturesToTrack(img, featuresCurrent, 50, 0.0005, 16); //calculate the features for use in next iteration



            // Track points of interest in current image:
            calcOpticalFlowPyrLK(prevgray, img, featuresPrevious, featuresNextPos, featuresFound, err);
            err.release();

            //printf("featuresNextPos length: %d \n", (int)featuresNextPos.size());
            //printf("featuresfound length: %d \n", (int)featuresFound.size());
            //Draw lines connecting previous position and current position
            for (size_t i = 0; i<featuresNextPos.size(); i++) {
                if (featuresFound[i]) {

                    float dist = sqrt(pow(std::abs(featuresPrevious[i].x - featuresNextPos[i].x), 2) + pow(std::abs(featuresPrevious[i].y - featuresNextPos[i].y), 2));
                    if (dist > 15) {
                        // printf("The distance is too great to make sense \n");
                    }
                    else {
                        //Draw line from previous features to next features:
                        line(img, featuresPrevious[i], featuresNextPos[i], cv::Scalar(255, 0, 0));
                        if (std::abs(featuresPrevious[i].y - featuresNextPos[i].y)>9)
                        {
                            printf("Satellite might be found? Distance is: %f \n", dist);
                            //printf("Path of image containing satellite: %s \n", p.path().string());
                        }
                    }

                    //Draw the features:
                    circle(img, featuresNextPos[i], 3, cv::Scalar(255, 0, 0),2);
                }
            }


        }
        else {
            printf("Go here First\n");
            goodFeaturesToTrack(img, featuresCurrent, 50, 0.005, 16); //calculate the features for use in next iteration

            //Move current image into "previous" image:
            img.copyTo(prevgray);
        }

        // Print image to show
        cv::namedWindow("Tracking Current", cv::WINDOW_AUTOSIZE);
        imshow("Tracking Current", img);


        img.copyTo(prevgray);

        // wait for image to be printed
        cv::waitKey(10);
        //free memory again
        img.release();
    }


    cv::waitKey(0);
    return 0;

}

使用像

这样的本地视图变量

alert.setView(R.layout.alert_edit_information1);

然后使用

View view = inflater.inflate(R.layout. alert_edit_information1, null);

现在你可以用v - ＆gt;初始化一个edittext图。

alert.setView(view);

在自定义警报对话框上设置Edittext的文本

3 个答案: