質問編集履歴

2 logが反映されない MasakazuFukami score 1836 2016/01/05 00:05 投稿

Androidアプリ開発（超初心者）

いつもお世話になっております。

Androidの開発をはじめて1時間目です。

サンプルアプリでHello worldと表示させた後にその文字を別の文字（Hello New World）に変更するだけで積んでしまいました。。。

コードはこちらになります。

```java

package jp.study.myapplication;

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.View;

import android.view.Menu;

import android.view.MenuItem;

import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

TextView textview = (TextView)findViewById(R.id.text);

textview.setText("Hello New World!!");

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);

}

```

![xml](92cf9245e2eed7e02ae8d76aa729ad1b.png)

ここから下がlog

```yml

```java

01-04 23:48:55.439 15002-15002/? I/art: Not late-enabling -Xcheck:jni (already on)

01-04 23:48:55.508 15002-15002/jp.study.myapplication W/System: ClassLoader referenced unknown path: /data/app/jp.study.myapplication-2/lib/x86

01-04 23:48:55.633 15002-15002/jp.study.myapplication D/AndroidRuntime: Shutting down VM

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: FATAL EXCEPTION: main

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: Process: jp.study.myapplication, PID: 15002

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{jp.study.myapplication/jp.study.myapplication.MainActivity}: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.TextView

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at android.app.ActivityThread.-wrap11(ActivityThread.java)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:102)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at android.os.Looper.loop(Looper.java:148)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5417)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: Caused by: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.TextView

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at jp.study.myapplication.MainActivity.onCreate(MainActivity.java:19)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at android.app.Activity.performCreate(Activity.java:6237)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)

01-04 23:48:55.635 15002-15002/jp.study.myapplication E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)