如何在 Android 中显示带有百分比的 ProgressBar 示例

Question

我有一项任务是ProgressBar在其上添加带有百分比值的值，以在用户想要预测某些内容时显示一个值。我没有使用，ProgressDialog因为它现在已被弃用。此处，百分比值取决于从请求开始到完成所用的时间。我正在使用Volley从服务器获取数据。

这是我要实现的目标的示例图像：

我已经这样做了

我在警报对话框中实现了一个水平进度条（我使用这种方式是因为进度对话框已被弃用）。我想像这样设置进度条。

public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    view =  inflater.inflate(R.layout.fragment_result_prediction, container, false);
    predictProgress = (ProgressBar) view.findViewById(R.id.progressbarPredict);
    AlertDialog.Builder(view.getContext());
    builder.setCancelable(false); // if you want user to wait for some process to finish,
    View v = inflater.inflate(R.layout.layout_loading_dialog, null);
    builder.setView(v);
    final AlertDialog dialog = builder.create();
    submitPredictPlant.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
                dialog.show();
                predictProgress.setProgress(25);
                predictProgress.setProgress(50);
                predictProgress.setProgress(75);
                predictProgress.setProgress(100);
                dialog.dismiss();

当进度为 100 时，我想关闭对话框。但这会出现类似错误

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ProgressBar.setProgress(int)' on a null object reference

我已经参考了 builder.setview 中使用的 layout_loading_dialog 中的进度条。

这是 layout_loading_dialog.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="20dp">
<TextView
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_weight="4"
    android:gravity="center"
    android:text="Please wait! This may take a moment." />

<ProgressBar
    android:layout_width="match_parent"
    android:id="@+id/progressbarPredict"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    style="?android:attr/progressBarStyleHorizontal"/>

Answer 1

以下是创建具有百分比的进度对话框的代码，如图所示。

int status = 0;
Handler handler = new Handler();

public void showDialog(Activity activity, String msg) {
    final Dialog dialog = new Dialog(activity);
    dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
    dialog.setCancelable(false);
    dialog.setContentView(R.layout.dialog);

    final ProgressBar text = (ProgressBar) dialog.findViewById(R.id.progress_horizontal);
    final TextView text2 = dialog.findViewById(R.id.value123);


    new Thread(new Runnable() {
        @Override
        public void run() {
            while (status < 100) {

                status += 1;

                try {
                    Thread.sleep(200);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                handler.post(new Runnable() {
                    @Override
                    public void run() {

                        text.setProgress(status);
                        text2.setText(String.valueOf(status));

                        if (status == 100) {
                            dialog.dismiss();
                        }
                    }
                });
            }
        }
    }).start();


    dialog.show();

    Window window = dialog.getWindow();
    window.setLayout(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.WRAP_CONTENT);
}

布局文件：对话框

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:layout_gravity="center"
android:orientation="vertical">

<ProgressBar
    android:id="@+id/progress_horizontal"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="16dp" />

<RelativeLayout
    android:layout_width="wrap_content"
    android:paddingLeft="20dp"
    android:layout_margin="16dp"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/value123"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
      />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/value123"
        android:text="%" />
</RelativeLayout>

结果 ：

使用异步任务：

int status = 0;
Handler handler = new Handler();
Dialog dialog;
ProgressBar text;
TextView text2;

public void showDialog(Activity activity, String msg) {
    dialog = new Dialog(activity);
    dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
    dialog.setCancelable(false);
    dialog.setContentView(R.layout.dialog);

    text = (ProgressBar) dialog.findViewById(R.id.progress_horizontal);
    text2 = dialog.findViewById(R.id.value123);


    dialog.show();

    Window window = dialog.getWindow();
    window.setLayout(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.WRAP_CONTENT);

    new Thread(new Runnable() {
        @Override
        public void run() {
            while (status < 100) {

                status += 1;

                try {
                    Thread.sleep(200);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                handler.post(new Runnable() {
                    @Override
                    public void run() {

                        text.setProgress(status);
                        text2.setText(String.valueOf(status));

                        if (status == 100) {
                            status = 0;
                        }
                    }
                });
            }
        }
    }).start();

}


private class AsyncTaskRunner extends AsyncTask<String, String, String> {

    @Override
    protected String doInBackground(String... params) {


        // it will fill the progress bar to 100
        // and will refill again and again



        /*
         *
         * Make your api call here
         * MAke request to API and return data when response comes
         *
         *
         * */

        /*
        * 
        * I have just add sleep to thead for example purposes
        * 
        * */
        try {
            Thread.sleep(30 * 1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        return resp;
    }


    @Override
    protected void onPostExecute(String result) {


        /*
         *
         *
         * Do your processing there on the api result
         *
         *
         * */
        dialog.dismiss();
    }


    @Override
    protected void onPreExecute() {
        showDialog(MainActivity.this,"");

    }


    @Override
    protected void onProgressUpdate(String... text) {

    }
}

启动 Asyntask ：

    new AsyncTaskRunner().execute("fs");

我不确定这是否是最好的方法