Question

我是Android开发的学习者，我在需要你帮助的程序中学习SQLite数据库。

我开发的程序从用户那里获取输入并将值存储在SQLite数据库中，我还制作了一个可点击的文本视图，用于显示存储的数据。

我面临的问题是，当我运行程序并直接点击显示数据（Textview）时，它会打开警报对话框并显示数据，但是当我输入数据时，如果我尝试点击＆＃ 34;显示数据＆＃34;文本视图被禁用。

请帮忙。

以下是我的XML和Java文件。

XML

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.junaidmalik.sqlitedemo.SqliteDemo">

    <EditText
        android:id="@+id/rollnum"
        android:hint="Enter Roll Number"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:ems="10"
        android:inputType="number"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.503"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.16" />

    <EditText
        android:id="@+id/name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:ems="10"
        android:inputType="textPersonName"
        android:hint="Enter Name"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.503"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/rollnum"
        app:layout_constraintVertical_bias="0.018" />

    <EditText
        android:id="@+id/marks"
        android:hint="Enter Marks"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:ems="10"
        android:inputType="number"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.503"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/name"
        app:layout_constraintVertical_bias="0.03" />

    <Button
        android:id="@+id/btnupdt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="Update"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/marks"
        app:layout_constraintVertical_bias="0.125" />

    <TextView
        android:textAppearance="@style/Base.TextAppearance.AppCompat.Large"
        android:id="@+id/search"
        android:clickable="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="Show Data >>"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btnupdt" />
</android.support.constraint.ConstraintLayout>

以下是Java文件

package com.example.junaidmalik.sqlitedemo;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class SqliteDemo extends AppCompatActivity {

    EditText et1, et2, et3;
    TextView search;
    SqliteDemoHelper myData;

    Button btnupdt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sqlite_demo);

        et1 = (EditText) findViewById(R.id.rollnum);
        et2 = (EditText) findViewById(R.id.name);
        et3 = (EditText) findViewById(R.id.marks);
        search = (TextView) findViewById(R.id.search);

        btnupdt = (Button) findViewById(R.id.btnupdt);

        btnupdt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                int rn = Integer.parseInt(et1.getText().toString());
                int mks = Integer.parseInt(et3.getText().toString());
                String name = (String) et2.getText().toString();

                SqliteDemoHelper demoHelper = new SqliteDemoHelper(SqliteDemo.this);
                SQLiteDatabase db = demoHelper.getWritableDatabase();

                ContentValues values = new ContentValues();
                values.put("sid", rn);
                values.put("sname", name);
                values.put("marks", mks);

                long row = db.insert("Students", null, values);

                demoHelper.getReadableDatabase();

                String projection[] = {"sid", "sname", "marks"};

                Cursor c = db.query("Students", projection, null, null, null, null, null);
                c.moveToLast();
                System.out.println("Name is : " + c.getString(1) + " and " + "Roll Number is :" + c.getString(0));
                Toast.makeText(SqliteDemo.this, "Database Updated", Toast.LENGTH_SHORT).show();

                setContentView(R.layout.activity_sqlite_demo);

            }

        });

        search.setOnClickListener(new View.OnClickListener() {


            @Override
            public void onClick(View view) {

                setContentView(R.layout.activity_sqlite_demo);

                SqliteDemoHelper demoHelper = new SqliteDemoHelper(SqliteDemo.this);
                SQLiteDatabase db = demoHelper.getWritableDatabase();
                Cursor res = db.rawQuery("Select * from Students",null);



                if (res.getCount() == 0) {
                    showMessage("Error", "Nothing Found");
                    return;
                }

                StringBuffer buffer = new StringBuffer();
                while (res.moveToNext()) {
                    buffer.append("sid :" + res.getString(0) + "\n");
                    buffer.append("name : " + res.getString(1) + "\n");
                    buffer.append("Marks :" + res.getString(2) + "\n\n");
                }

                showMessage("Data is - ", buffer.toString());

            }
        });}


    public void showMessage(String title, String message) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setCancelable(true);
        builder.setTitle(title);
        builder.setMessage(message);
        builder.show();
    }

}

Answer 1

search.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            setContentView(R.layout.activity_sqlite_demo);
....
..
}});

从搜索点击事件中删除setcontentView。

如果再次调用方法setcontentview，可能在布局中查看activity_sqlite_demo需要重新信任。

可点击的文本视图不起作用

1 个答案: