{"id":21132,"date":"2022-11-12T06:58:26","date_gmt":"2022-11-12T01:28:26","guid":{"rendered":"https:\/\/jassweb.com\/solved\/solved-whats-wrong-with-my-code-please-help-me-duplicate\/"},"modified":"2022-11-12T06:58:26","modified_gmt":"2022-11-12T01:28:26","slug":"solved-whats-wrong-with-my-code-please-help-me-duplicate","status":"publish","type":"post","link":"https:\/\/jassweb.com\/solved\/solved-whats-wrong-with-my-code-please-help-me-duplicate\/","title":{"rendered":"[Solved] What’s wrong with my code, please help me [duplicate]"},"content":{"rendered":"

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Firstly, your MediaPlayer<\/code> instance should reside within MainActivity<\/code>, not MyListener<\/code>, and MyListener<\/code> should not extend an activity. In fact, you should move all of your code from MyListener<\/code> into MainActivity<\/code>, I don’t really see a purpose for it in the snippet you’ve provided.<\/p>\n

Secondly, You’re creating your MediaPlayer<\/code> outside of the Activity Lifecycle<\/a>, while still trying to pass a Context to it:<\/p>\n

public class MainActivity extends AppCompatActivity {\n\n    MediaPlayer musicPlayer = MediaPlayer.create(this, R.raw.sound_file);\n    ...\n}\n<\/code><\/pre>\n
The activity has no Context (this<\/code>) until the Activity Lifecycle has started, the way you’ve written it above is equivalent to defining musicPlayer<\/code> in a constructor:<\/p>\n
public class MainActivity extends AppCompatActivity {\n\n    MediaPlayer musicPlayer; \n\n    public MyListener() {\n        musicPlayer = MediaPlayer.create(this, R.raw.sound_file);\n    }\n    ...\n}\n<\/code><\/pre>\n
This will also fail as the Activity Lifecycle has not yet started. What you need to do is declare musicPlayer<\/code> as a member of the class, and then create an instance in onCreate()<\/code> where the Context will have been initialsed:<\/p>\n
public class MainActivity extends AppCompatActivity {\n\n    MediaPlayer musicPlayer; \n\n    @Override\n    protected void onCreate(Bundle savedInstanceState) {\n        super.onCreate(savedInstanceState);\n        setContentView(R.layout.activity_my_listener);\n        musicPlayer = MediaPlayer.create(this, R.raw.sound_file);\n    }\n    ...\n}\n<\/code><\/pre>\n
\n
To address your comment, here’s an example of how it could all fit in to your MainActivity<\/code> using lambdas<\/a>:<\/p>\n
public class MainActivity extends AppCompatActivity {\n\n    int currentPosition;\n    MediaPlayer musicPlayer;\n\n    @Override\n    protected void onCreate(Bundle savedInstanceState) {\n        super.onCreate(savedInstanceState);\n        setContentView(R.layout.activity_main);\n        musicPlayer = MediaPlayer.create(this, R.raw.sound_file);\n\n        Button startButton = (Button) findViewById(R.id.start);\n        startButton.setOnClickListener(view -> musicPlayer.start());\n\n        Button pauseButton = (Button) findViewById(R.id.pause);\n        pauseButton.setOnClickListener(view -> musicPlayer.pause());\n    }\n}\n<\/code><\/pre>\n<\/p><\/div>\n
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            4<\/span> <\/p><\/div>\n<\/div>\n
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solved What’s wrong with my code, please help me [duplicate] <\/p>\n","protected":false},"excerpt":{"rendered":"
[ad_1] Firstly, your MediaPlayer instance should reside within MainActivity, not MyListener, and MyListener should not extend an activity. In fact, you should move all of your code from MyListener into MainActivity, I don’t really see a purpose for it in the snippet you’ve provided. Secondly, You’re creating your MediaPlayer outside of the Activity Lifecycle, while … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[320],"tags":[452,323,328],"class_list":["post-21132","post","type-post","status-publish","format-standard","hentry","category-solved","tag-android","tag-java","tag-nullpointerexception"],"yoast_head":"\n[Solved] What's wrong with my code, please help me [duplicate] - JassWeb<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/jassweb.com\/solved\/solved-whats-wrong-with-my-code-please-help-me-duplicate\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"[Solved] What's wrong with my code, please help me [duplicate] - JassWeb\" \/>\n<meta property=\"og:description\" content=\"[ad_1] Firstly, your MediaPlayer instance should reside within MainActivity, not MyListener, and MyListener should not extend an activity. 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