我的应用按钮不起作用

Question

我正在尝试创建一个应用程序，该应用程序在按下按钮时会更改显示的文本。但是它不起作用。我检查了我的代码，我没有发现我的事件处理程序有任何问题。这是我的代码：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       //Reference Button
        Button ekeButton = (Button)findViewById(R.id.ekeButton);

        ekeButton.setOnClickListener(
                new View.OnClickListener() {
                    public void onClick(View view) {
                        TextView displayText = (TextView) findViewById(R.id.displayText);
                        displayText.setText(R.string.NewMassage);

                    }
                }
        );

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });    
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

这是我更新的代码：

    package com.mesoft.eventhandler;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       //Reference Button
        Button ekeButton = (Button)findViewById(R.id.ekeButton);
        final TextView displayText = (TextView) findViewById(R.id.displayText);


        ekeButton.setOnClickListener(
                new View.OnClickListener() {
                    public void onClick(View view) {
                        displayText.setText(getString(R.string.NewMassage));

                    }
                }
        );



        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });





    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

我在我的 string.xml 中声明了我的字符串 代码如下：

    <resources>
    <string name="app_name">Event Handler</string>
    <string name="action_settings">Settings</string>
    <string name="click">Choose Massage</string>
    <string name="ShowMassage">Merry Xmas</string>
    <string name="NewMassage">Happy new year</string>
</resources>

这里是activity_main.xml代码：

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".MainActivity"
    tools:showIn="@layout/activity_main">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="@string/ShowMassage"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="90dp"
        android:id="@+id/displayText" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/click"
        android:id="@+id/ekeButton"
        android:layout_marginTop="74dp"
        android:enabled="false"
        android:layout_below="@+id/displayText"
        android:layout_alignLeft="@+id/displayText"
        android:layout_alignStart="@+id/displayText"
        android:textColor="#090909" />
</RelativeLayout>

Answer 1

改变这一行

displayText.setText(R.string.NewMassage);

与

displayText.setText(getResources().getString(R.string.NewMassage));

R.string.NewMassage 以Integer 的形式返回NewMassage 字符串资源的id。

正如activesince93 所说，在按钮 OnclickListener 外声明您的 textView

Answer 2

替换这个，

displayText.setText(R.string.NewMassage);

与

displayText.setText(getString(R.string.NewMassage));

还有，

最好声明

TextView displayText = (TextView) findViewById(R.id.displayText);

在onClick() 方法之外。我的意思是在下面

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

注意：确保你在strings.xml中声明了NewMassage

<string name="NewMassage">Text you want to display</string>